[3] | 1 | # expression.py |
---|
| 2 | # Copyright (C) 2005, 2006, 2007, 2008, 2009 Michael Bayer mike_mp@zzzcomputing.com |
---|
| 3 | # |
---|
| 4 | # This module is part of SQLAlchemy and is released under |
---|
| 5 | # the MIT License: http://www.opensource.org/licenses/mit-license.php |
---|
| 6 | |
---|
| 7 | """Defines the base components of SQL expression trees. |
---|
| 8 | |
---|
| 9 | All components are derived from a common base class |
---|
| 10 | :class:`~sqlalchemy.sql.expression.ClauseElement`. Common behaviors are organized |
---|
| 11 | based on class hierarchies, in some cases via mixins. |
---|
| 12 | |
---|
| 13 | All object construction from this package occurs via functions which |
---|
| 14 | in some cases will construct composite ``ClauseElement`` structures |
---|
| 15 | together, and in other cases simply return a single ``ClauseElement`` |
---|
| 16 | constructed directly. The function interface affords a more "DSL-ish" |
---|
| 17 | feel to constructing SQL expressions and also allows future class |
---|
| 18 | reorganizations. |
---|
| 19 | |
---|
| 20 | Even though classes are not constructed directly from the outside, |
---|
| 21 | most classes which have additional public methods are considered to be |
---|
| 22 | public (i.e. have no leading underscore). Other classes which are |
---|
| 23 | "semi-public" are marked with a single leading underscore; these |
---|
| 24 | classes usually have few or no public methods and are less guaranteed |
---|
| 25 | to stay the same in future releases. |
---|
| 26 | |
---|
| 27 | """ |
---|
| 28 | |
---|
| 29 | import itertools, re |
---|
| 30 | from operator import attrgetter |
---|
| 31 | |
---|
| 32 | from sqlalchemy import util, exc |
---|
| 33 | from sqlalchemy.sql import operators |
---|
| 34 | from sqlalchemy.sql.visitors import Visitable, cloned_traverse |
---|
| 35 | from sqlalchemy import types as sqltypes |
---|
| 36 | import operator |
---|
| 37 | |
---|
| 38 | functions, schema, sql_util = None, None, None |
---|
| 39 | DefaultDialect, ClauseAdapter, Annotated = None, None, None |
---|
| 40 | |
---|
| 41 | __all__ = [ |
---|
| 42 | 'Alias', 'ClauseElement', |
---|
| 43 | 'ColumnCollection', 'ColumnElement', |
---|
| 44 | 'CompoundSelect', 'Delete', 'FromClause', 'Insert', 'Join', |
---|
| 45 | 'Select', 'Selectable', 'TableClause', 'Update', 'alias', 'and_', 'asc', |
---|
| 46 | 'between', 'bindparam', 'case', 'cast', 'column', 'delete', |
---|
| 47 | 'desc', 'distinct', 'except_', 'except_all', 'exists', 'extract', 'func', |
---|
| 48 | 'modifier', 'collate', |
---|
| 49 | 'insert', 'intersect', 'intersect_all', 'join', 'label', 'literal', |
---|
| 50 | 'literal_column', 'not_', 'null', 'or_', 'outparam', 'outerjoin', 'select', |
---|
| 51 | 'subquery', 'table', 'text', 'union', 'union_all', 'update', ] |
---|
| 52 | |
---|
| 53 | |
---|
| 54 | |
---|
| 55 | def desc(column): |
---|
| 56 | """Return a descending ``ORDER BY`` clause element. |
---|
| 57 | |
---|
| 58 | e.g.:: |
---|
| 59 | |
---|
| 60 | order_by = [desc(table1.mycol)] |
---|
| 61 | |
---|
| 62 | """ |
---|
| 63 | return _UnaryExpression(column, modifier=operators.desc_op) |
---|
| 64 | |
---|
| 65 | def asc(column): |
---|
| 66 | """Return an ascending ``ORDER BY`` clause element. |
---|
| 67 | |
---|
| 68 | e.g.:: |
---|
| 69 | |
---|
| 70 | order_by = [asc(table1.mycol)] |
---|
| 71 | |
---|
| 72 | """ |
---|
| 73 | return _UnaryExpression(column, modifier=operators.asc_op) |
---|
| 74 | |
---|
| 75 | def outerjoin(left, right, onclause=None): |
---|
| 76 | """Return an ``OUTER JOIN`` clause element. |
---|
| 77 | |
---|
| 78 | The returned object is an instance of :class:`~sqlalchemy.sql.expression.Join`. |
---|
| 79 | |
---|
| 80 | Similar functionality is also available via the ``outerjoin()`` |
---|
| 81 | method on any :class:`~sqlalchemy.sql.expression.FromClause`. |
---|
| 82 | |
---|
| 83 | left |
---|
| 84 | The left side of the join. |
---|
| 85 | |
---|
| 86 | right |
---|
| 87 | The right side of the join. |
---|
| 88 | |
---|
| 89 | onclause |
---|
| 90 | Optional criterion for the ``ON`` clause, is derived from |
---|
| 91 | foreign key relationships established between left and right |
---|
| 92 | otherwise. |
---|
| 93 | |
---|
| 94 | To chain joins together, use the ``join()`` or ``outerjoin()`` |
---|
| 95 | methods on the resulting ``Join`` object. |
---|
| 96 | |
---|
| 97 | """ |
---|
| 98 | return Join(left, right, onclause, isouter=True) |
---|
| 99 | |
---|
| 100 | def join(left, right, onclause=None, isouter=False): |
---|
| 101 | """Return a ``JOIN`` clause element (regular inner join). |
---|
| 102 | |
---|
| 103 | The returned object is an instance of :class:`~sqlalchemy.sql.expression.Join`. |
---|
| 104 | |
---|
| 105 | Similar functionality is also available via the ``join()`` method |
---|
| 106 | on any :class:`~sqlalchemy.sql.expression.FromClause`. |
---|
| 107 | |
---|
| 108 | left |
---|
| 109 | The left side of the join. |
---|
| 110 | |
---|
| 111 | right |
---|
| 112 | The right side of the join. |
---|
| 113 | |
---|
| 114 | onclause |
---|
| 115 | Optional criterion for the ``ON`` clause, is derived from |
---|
| 116 | foreign key relationships established between left and right |
---|
| 117 | otherwise. |
---|
| 118 | |
---|
| 119 | To chain joins together, use the ``join()`` or ``outerjoin()`` |
---|
| 120 | methods on the resulting ``Join`` object. |
---|
| 121 | |
---|
| 122 | """ |
---|
| 123 | return Join(left, right, onclause, isouter) |
---|
| 124 | |
---|
| 125 | def select(columns=None, whereclause=None, from_obj=[], **kwargs): |
---|
| 126 | """Returns a ``SELECT`` clause element. |
---|
| 127 | |
---|
| 128 | Similar functionality is also available via the ``select()`` |
---|
| 129 | method on any :class:`~sqlalchemy.sql.expression.FromClause`. |
---|
| 130 | |
---|
| 131 | The returned object is an instance of :class:`~sqlalchemy.sql.expression.Select`. |
---|
| 132 | |
---|
| 133 | All arguments which accept ``ClauseElement`` arguments also accept |
---|
| 134 | string arguments, which will be converted as appropriate into |
---|
| 135 | either ``text()`` or ``literal_column()`` constructs. |
---|
| 136 | |
---|
| 137 | columns |
---|
| 138 | A list of ``ClauseElement`` objects, typically ``ColumnElement`` |
---|
| 139 | objects or subclasses, which will form the columns clause of the |
---|
| 140 | resulting statement. For all members which are instances of |
---|
| 141 | ``Selectable``, the individual ``ColumnElement`` members of the |
---|
| 142 | ``Selectable`` will be added individually to the columns clause. |
---|
| 143 | For example, specifying a ``Table`` instance will result in all |
---|
| 144 | the contained ``Column`` objects within to be added to the |
---|
| 145 | columns clause. |
---|
| 146 | |
---|
| 147 | This argument is not present on the form of ``select()`` |
---|
| 148 | available on ``Table``. |
---|
| 149 | |
---|
| 150 | whereclause |
---|
| 151 | A ``ClauseElement`` expression which will be used to form the |
---|
| 152 | ``WHERE`` clause. |
---|
| 153 | |
---|
| 154 | from_obj |
---|
| 155 | A list of ``ClauseElement`` objects which will be added to the |
---|
| 156 | ``FROM`` clause of the resulting statement. Note that "from" |
---|
| 157 | objects are automatically located within the columns and |
---|
| 158 | whereclause ClauseElements. Use this parameter to explicitly |
---|
| 159 | specify "from" objects which are not automatically locatable. |
---|
| 160 | This could include ``Table`` objects that aren't otherwise |
---|
| 161 | present, or ``Join`` objects whose presence will supercede that |
---|
| 162 | of the ``Table`` objects already located in the other clauses. |
---|
| 163 | |
---|
| 164 | \**kwargs |
---|
| 165 | Additional parameters include: |
---|
| 166 | |
---|
| 167 | autocommit |
---|
| 168 | indicates this SELECT statement modifies the database, and |
---|
| 169 | should be subject to autocommit behavior if no transaction |
---|
| 170 | has been started. |
---|
| 171 | |
---|
| 172 | prefixes |
---|
| 173 | a list of strings or ``ClauseElement`` objects to include |
---|
| 174 | directly after the SELECT keyword in the generated statement, |
---|
| 175 | for dialect-specific query features. |
---|
| 176 | |
---|
| 177 | distinct=False |
---|
| 178 | when ``True``, applies a ``DISTINCT`` qualifier to the columns |
---|
| 179 | clause of the resulting statement. |
---|
| 180 | |
---|
| 181 | use_labels=False |
---|
| 182 | when ``True``, the statement will be generated using labels |
---|
| 183 | for each column in the columns clause, which qualify each |
---|
| 184 | column with its parent table's (or aliases) name so that name |
---|
| 185 | conflicts between columns in different tables don't occur. |
---|
| 186 | The format of the label is <tablename>_<column>. The "c" |
---|
| 187 | collection of the resulting ``Select`` object will use these |
---|
| 188 | names as well for targeting column members. |
---|
| 189 | |
---|
| 190 | for_update=False |
---|
| 191 | when ``True``, applies ``FOR UPDATE`` to the end of the |
---|
| 192 | resulting statement. Certain database dialects also support |
---|
| 193 | alternate values for this parameter, for example mysql |
---|
| 194 | supports "read" which translates to ``LOCK IN SHARE MODE``, |
---|
| 195 | and oracle supports "nowait" which translates to ``FOR UPDATE |
---|
| 196 | NOWAIT``. |
---|
| 197 | |
---|
| 198 | correlate=True |
---|
| 199 | indicates that this ``Select`` object should have its |
---|
| 200 | contained ``FromClause`` elements "correlated" to an enclosing |
---|
| 201 | ``Select`` object. This means that any ``ClauseElement`` |
---|
| 202 | instance within the "froms" collection of this ``Select`` |
---|
| 203 | which is also present in the "froms" collection of an |
---|
| 204 | enclosing select will not be rendered in the ``FROM`` clause |
---|
| 205 | of this select statement. |
---|
| 206 | |
---|
| 207 | group_by |
---|
| 208 | a list of ``ClauseElement`` objects which will comprise the |
---|
| 209 | ``GROUP BY`` clause of the resulting select. |
---|
| 210 | |
---|
| 211 | having |
---|
| 212 | a ``ClauseElement`` that will comprise the ``HAVING`` clause |
---|
| 213 | of the resulting select when ``GROUP BY`` is used. |
---|
| 214 | |
---|
| 215 | order_by |
---|
| 216 | a scalar or list of ``ClauseElement`` objects which will |
---|
| 217 | comprise the ``ORDER BY`` clause of the resulting select. |
---|
| 218 | |
---|
| 219 | limit=None |
---|
| 220 | a numerical value which usually compiles to a ``LIMIT`` |
---|
| 221 | expression in the resulting select. Databases that don't |
---|
| 222 | support ``LIMIT`` will attempt to provide similar |
---|
| 223 | functionality. |
---|
| 224 | |
---|
| 225 | offset=None |
---|
| 226 | a numeric value which usually compiles to an ``OFFSET`` |
---|
| 227 | expression in the resulting select. Databases that don't |
---|
| 228 | support ``OFFSET`` will attempt to provide similar |
---|
| 229 | functionality. |
---|
| 230 | |
---|
| 231 | bind=None |
---|
| 232 | an ``Engine`` or ``Connection`` instance to which the |
---|
| 233 | resulting ``Select ` object will be bound. The ``Select`` |
---|
| 234 | object will otherwise automatically bind to whatever |
---|
| 235 | ``Connectable`` instances can be located within its contained |
---|
| 236 | ``ClauseElement`` members. |
---|
| 237 | |
---|
| 238 | scalar=False |
---|
| 239 | deprecated. Use select(...).as_scalar() to create a "scalar |
---|
| 240 | column" proxy for an existing Select object. |
---|
| 241 | |
---|
| 242 | """ |
---|
| 243 | if 'scalar' in kwargs: |
---|
| 244 | util.warn_deprecated('scalar option is deprecated; see docs for details') |
---|
| 245 | scalar = kwargs.pop('scalar', False) |
---|
| 246 | s = Select(columns, whereclause=whereclause, from_obj=from_obj, **kwargs) |
---|
| 247 | if scalar: |
---|
| 248 | return s.as_scalar() |
---|
| 249 | else: |
---|
| 250 | return s |
---|
| 251 | |
---|
| 252 | def subquery(alias, *args, **kwargs): |
---|
| 253 | """Return an :class:`~sqlalchemy.sql.expression.Alias` object derived from a :class:`~sqlalchemy.sql.expression.Select`. |
---|
| 254 | |
---|
| 255 | name |
---|
| 256 | alias name |
---|
| 257 | |
---|
| 258 | \*args, \**kwargs |
---|
| 259 | |
---|
| 260 | all other arguments are delivered to the :func:`~sqlalchemy.sql.expression.select` |
---|
| 261 | function. |
---|
| 262 | |
---|
| 263 | """ |
---|
| 264 | return Select(*args, **kwargs).alias(alias) |
---|
| 265 | |
---|
| 266 | def insert(table, values=None, inline=False, **kwargs): |
---|
| 267 | """Return an :class:`~sqlalchemy.sql.expression.Insert` clause element. |
---|
| 268 | |
---|
| 269 | Similar functionality is available via the ``insert()`` method on |
---|
| 270 | :class:`~sqlalchemy.schema.Table`. |
---|
| 271 | |
---|
| 272 | :param table: The table to be inserted into. |
---|
| 273 | |
---|
| 274 | :param values: A dictionary which specifies the column specifications of the |
---|
| 275 | ``INSERT``, and is optional. If left as None, the column |
---|
| 276 | specifications are determined from the bind parameters used |
---|
| 277 | during the compile phase of the ``INSERT`` statement. If the |
---|
| 278 | bind parameters also are None during the compile phase, then the |
---|
| 279 | column specifications will be generated from the full list of |
---|
| 280 | table columns. Note that the :meth:`~Insert.values()` generative method |
---|
| 281 | may also be used for this. |
---|
| 282 | |
---|
| 283 | :param prefixes: A list of modifier keywords to be inserted between INSERT and INTO. |
---|
| 284 | Alternatively, the :meth:`~Insert.prefix_with` generative method may be used. |
---|
| 285 | |
---|
| 286 | :param inline: |
---|
| 287 | if True, SQL defaults will be compiled 'inline' into the statement |
---|
| 288 | and not pre-executed. |
---|
| 289 | |
---|
| 290 | If both `values` and compile-time bind parameters are present, the |
---|
| 291 | compile-time bind parameters override the information specified |
---|
| 292 | within `values` on a per-key basis. |
---|
| 293 | |
---|
| 294 | The keys within `values` can be either ``Column`` objects or their |
---|
| 295 | string identifiers. Each key may reference one of: |
---|
| 296 | |
---|
| 297 | * a literal data value (i.e. string, number, etc.); |
---|
| 298 | * a Column object; |
---|
| 299 | * a SELECT statement. |
---|
| 300 | |
---|
| 301 | If a ``SELECT`` statement is specified which references this |
---|
| 302 | ``INSERT`` statement's table, the statement will be correlated |
---|
| 303 | against the ``INSERT`` statement. |
---|
| 304 | |
---|
| 305 | """ |
---|
| 306 | return Insert(table, values, inline=inline, **kwargs) |
---|
| 307 | |
---|
| 308 | def update(table, whereclause=None, values=None, inline=False, **kwargs): |
---|
| 309 | """Return an :class:`~sqlalchemy.sql.expression.Update` clause element. |
---|
| 310 | |
---|
| 311 | Similar functionality is available via the ``update()`` method on |
---|
| 312 | :class:`~sqlalchemy.schema.Table`. |
---|
| 313 | |
---|
| 314 | :param table: The table to be updated. |
---|
| 315 | |
---|
| 316 | :param whereclause: A ``ClauseElement`` describing the ``WHERE`` condition of the |
---|
| 317 | ``UPDATE`` statement. Note that the :meth:`~Update.where()` generative |
---|
| 318 | method may also be used for this. |
---|
| 319 | |
---|
| 320 | :param values: |
---|
| 321 | A dictionary which specifies the ``SET`` conditions of the |
---|
| 322 | ``UPDATE``, and is optional. If left as None, the ``SET`` |
---|
| 323 | conditions are determined from the bind parameters used during |
---|
| 324 | the compile phase of the ``UPDATE`` statement. If the bind |
---|
| 325 | parameters also are None during the compile phase, then the |
---|
| 326 | ``SET`` conditions will be generated from the full list of table |
---|
| 327 | columns. Note that the :meth:`~Update.values()` generative method may |
---|
| 328 | also be used for this. |
---|
| 329 | |
---|
| 330 | :param inline: |
---|
| 331 | if True, SQL defaults will be compiled 'inline' into the statement |
---|
| 332 | and not pre-executed. |
---|
| 333 | |
---|
| 334 | If both `values` and compile-time bind parameters are present, the |
---|
| 335 | compile-time bind parameters override the information specified |
---|
| 336 | within `values` on a per-key basis. |
---|
| 337 | |
---|
| 338 | The keys within `values` can be either ``Column`` objects or their |
---|
| 339 | string identifiers. Each key may reference one of: |
---|
| 340 | |
---|
| 341 | * a literal data value (i.e. string, number, etc.); |
---|
| 342 | * a Column object; |
---|
| 343 | * a SELECT statement. |
---|
| 344 | |
---|
| 345 | If a ``SELECT`` statement is specified which references this |
---|
| 346 | ``UPDATE`` statement's table, the statement will be correlated |
---|
| 347 | against the ``UPDATE`` statement. |
---|
| 348 | |
---|
| 349 | """ |
---|
| 350 | return Update(table, whereclause=whereclause, values=values, inline=inline, **kwargs) |
---|
| 351 | |
---|
| 352 | def delete(table, whereclause = None, **kwargs): |
---|
| 353 | """Return a :class:`~sqlalchemy.sql.expression.Delete` clause element. |
---|
| 354 | |
---|
| 355 | Similar functionality is available via the ``delete()`` method on |
---|
| 356 | :class:`~sqlalchemy.schema.Table`. |
---|
| 357 | |
---|
| 358 | :param table: The table to be updated. |
---|
| 359 | |
---|
| 360 | :param whereclause: A :class:`ClauseElement` describing the ``WHERE`` condition of the |
---|
| 361 | ``UPDATE`` statement. Note that the :meth:`~Delete.where()` generative method |
---|
| 362 | may be used instead. |
---|
| 363 | |
---|
| 364 | """ |
---|
| 365 | return Delete(table, whereclause, **kwargs) |
---|
| 366 | |
---|
| 367 | def and_(*clauses): |
---|
| 368 | """Join a list of clauses together using the ``AND`` operator. |
---|
| 369 | |
---|
| 370 | The ``&`` operator is also overloaded on all |
---|
| 371 | :class:`~sqlalchemy.sql.expression._CompareMixin` subclasses to produce the same |
---|
| 372 | result. |
---|
| 373 | |
---|
| 374 | """ |
---|
| 375 | if len(clauses) == 1: |
---|
| 376 | return clauses[0] |
---|
| 377 | return BooleanClauseList(operator=operators.and_, *clauses) |
---|
| 378 | |
---|
| 379 | def or_(*clauses): |
---|
| 380 | """Join a list of clauses together using the ``OR`` operator. |
---|
| 381 | |
---|
| 382 | The ``|`` operator is also overloaded on all |
---|
| 383 | :class:`~sqlalchemy.sql.expression._CompareMixin` subclasses to produce the same |
---|
| 384 | result. |
---|
| 385 | |
---|
| 386 | """ |
---|
| 387 | if len(clauses) == 1: |
---|
| 388 | return clauses[0] |
---|
| 389 | return BooleanClauseList(operator=operators.or_, *clauses) |
---|
| 390 | |
---|
| 391 | def not_(clause): |
---|
| 392 | """Return a negation of the given clause, i.e. ``NOT(clause)``. |
---|
| 393 | |
---|
| 394 | The ``~`` operator is also overloaded on all |
---|
| 395 | :class:`~sqlalchemy.sql.expression._CompareMixin` subclasses to produce the same |
---|
| 396 | result. |
---|
| 397 | |
---|
| 398 | """ |
---|
| 399 | return operators.inv(_literal_as_binds(clause)) |
---|
| 400 | |
---|
| 401 | def distinct(expr): |
---|
| 402 | """Return a ``DISTINCT`` clause.""" |
---|
| 403 | expr = _literal_as_binds(expr) |
---|
| 404 | return _UnaryExpression(expr, operator=operators.distinct_op, type_=expr.type) |
---|
| 405 | |
---|
| 406 | def between(ctest, cleft, cright): |
---|
| 407 | """Return a ``BETWEEN`` predicate clause. |
---|
| 408 | |
---|
| 409 | Equivalent of SQL ``clausetest BETWEEN clauseleft AND clauseright``. |
---|
| 410 | |
---|
| 411 | The ``between()`` method on all :class:`~sqlalchemy.sql.expression._CompareMixin` subclasses |
---|
| 412 | provides similar functionality. |
---|
| 413 | |
---|
| 414 | """ |
---|
| 415 | ctest = _literal_as_binds(ctest) |
---|
| 416 | return _BinaryExpression( |
---|
| 417 | ctest, |
---|
| 418 | ClauseList( |
---|
| 419 | _literal_as_binds(cleft, type_=ctest.type), |
---|
| 420 | _literal_as_binds(cright, type_=ctest.type), |
---|
| 421 | operator=operators.and_, |
---|
| 422 | group=False), |
---|
| 423 | operators.between_op) |
---|
| 424 | |
---|
| 425 | |
---|
| 426 | def case(whens, value=None, else_=None): |
---|
| 427 | """Produce a ``CASE`` statement. |
---|
| 428 | |
---|
| 429 | whens |
---|
| 430 | A sequence of pairs, or alternatively a dict, |
---|
| 431 | to be translated into "WHEN / THEN" clauses. |
---|
| 432 | |
---|
| 433 | value |
---|
| 434 | Optional for simple case statements, produces |
---|
| 435 | a column expression as in "CASE <expr> WHEN ..." |
---|
| 436 | |
---|
| 437 | else\_ |
---|
| 438 | Optional as well, for case defaults produces |
---|
| 439 | the "ELSE" portion of the "CASE" statement. |
---|
| 440 | |
---|
| 441 | The expressions used for THEN and ELSE, |
---|
| 442 | when specified as strings, will be interpreted |
---|
| 443 | as bound values. To specify textual SQL expressions |
---|
| 444 | for these, use the text(<string>) construct. |
---|
| 445 | |
---|
| 446 | The expressions used for the WHEN criterion |
---|
| 447 | may only be literal strings when "value" is |
---|
| 448 | present, i.e. CASE table.somecol WHEN "x" THEN "y". |
---|
| 449 | Otherwise, literal strings are not accepted |
---|
| 450 | in this position, and either the text(<string>) |
---|
| 451 | or literal(<string>) constructs must be used to |
---|
| 452 | interpret raw string values. |
---|
| 453 | |
---|
| 454 | Usage examples:: |
---|
| 455 | |
---|
| 456 | case([(orderline.c.qty > 100, item.c.specialprice), |
---|
| 457 | (orderline.c.qty > 10, item.c.bulkprice) |
---|
| 458 | ], else_=item.c.regularprice) |
---|
| 459 | case(value=emp.c.type, whens={ |
---|
| 460 | 'engineer': emp.c.salary * 1.1, |
---|
| 461 | 'manager': emp.c.salary * 3, |
---|
| 462 | }) |
---|
| 463 | |
---|
| 464 | """ |
---|
| 465 | |
---|
| 466 | return _Case(whens, value=value, else_=else_) |
---|
| 467 | |
---|
| 468 | def cast(clause, totype, **kwargs): |
---|
| 469 | """Return a ``CAST`` function. |
---|
| 470 | |
---|
| 471 | Equivalent of SQL ``CAST(clause AS totype)``. |
---|
| 472 | |
---|
| 473 | Use with a :class:`~sqlalchemy.types.TypeEngine` subclass, i.e:: |
---|
| 474 | |
---|
| 475 | cast(table.c.unit_price * table.c.qty, Numeric(10,4)) |
---|
| 476 | |
---|
| 477 | or:: |
---|
| 478 | |
---|
| 479 | cast(table.c.timestamp, DATE) |
---|
| 480 | |
---|
| 481 | """ |
---|
| 482 | return _Cast(clause, totype, **kwargs) |
---|
| 483 | |
---|
| 484 | def extract(field, expr): |
---|
| 485 | """Return the clause ``extract(field FROM expr)``.""" |
---|
| 486 | |
---|
| 487 | return _Extract(field, expr) |
---|
| 488 | |
---|
| 489 | def collate(expression, collation): |
---|
| 490 | """Return the clause ``expression COLLATE collation``.""" |
---|
| 491 | |
---|
| 492 | expr = _literal_as_binds(expression) |
---|
| 493 | return _BinaryExpression( |
---|
| 494 | expr, |
---|
| 495 | _literal_as_text(collation), |
---|
| 496 | operators.collate, type_=expr.type) |
---|
| 497 | |
---|
| 498 | def exists(*args, **kwargs): |
---|
| 499 | """Return an ``EXISTS`` clause as applied to a :class:`~sqlalchemy.sql.expression.Select` object. |
---|
| 500 | |
---|
| 501 | Calling styles are of the following forms:: |
---|
| 502 | |
---|
| 503 | # use on an existing select() |
---|
| 504 | s = select([table.c.col1]).where(table.c.col2==5) |
---|
| 505 | s = exists(s) |
---|
| 506 | |
---|
| 507 | # construct a select() at once |
---|
| 508 | exists(['*'], **select_arguments).where(criterion) |
---|
| 509 | |
---|
| 510 | # columns argument is optional, generates "EXISTS (SELECT *)" |
---|
| 511 | # by default. |
---|
| 512 | exists().where(table.c.col2==5) |
---|
| 513 | |
---|
| 514 | """ |
---|
| 515 | return _Exists(*args, **kwargs) |
---|
| 516 | |
---|
| 517 | def union(*selects, **kwargs): |
---|
| 518 | """Return a ``UNION`` of multiple selectables. |
---|
| 519 | |
---|
| 520 | The returned object is an instance of :class:`~sqlalchemy.sql.expression.CompoundSelect`. |
---|
| 521 | |
---|
| 522 | A similar ``union()`` method is available on all |
---|
| 523 | :class:`~sqlalchemy.sql.expression.FromClause` subclasses. |
---|
| 524 | |
---|
| 525 | \*selects |
---|
| 526 | a list of :class:`~sqlalchemy.sql.expression.Select` instances. |
---|
| 527 | |
---|
| 528 | \**kwargs |
---|
| 529 | available keyword arguments are the same as those of |
---|
| 530 | :func:`~sqlalchemy.sql.expression.select`. |
---|
| 531 | |
---|
| 532 | """ |
---|
| 533 | return _compound_select('UNION', *selects, **kwargs) |
---|
| 534 | |
---|
| 535 | def union_all(*selects, **kwargs): |
---|
| 536 | """Return a ``UNION ALL`` of multiple selectables. |
---|
| 537 | |
---|
| 538 | The returned object is an instance of :class:`~sqlalchemy.sql.expression.CompoundSelect`. |
---|
| 539 | |
---|
| 540 | A similar ``union_all()`` method is available on all |
---|
| 541 | :class:`~sqlalchemy.sql.expression.FromClause` subclasses. |
---|
| 542 | |
---|
| 543 | \*selects |
---|
| 544 | a list of :class:`~sqlalchemy.sql.expression.Select` instances. |
---|
| 545 | |
---|
| 546 | \**kwargs |
---|
| 547 | available keyword arguments are the same as those of |
---|
| 548 | :func:`~sqlalchemy.sql.expression.select`. |
---|
| 549 | |
---|
| 550 | """ |
---|
| 551 | return _compound_select('UNION ALL', *selects, **kwargs) |
---|
| 552 | |
---|
| 553 | def except_(*selects, **kwargs): |
---|
| 554 | """Return an ``EXCEPT`` of multiple selectables. |
---|
| 555 | |
---|
| 556 | The returned object is an instance of :class:`~sqlalchemy.sql.expression.CompoundSelect`. |
---|
| 557 | |
---|
| 558 | \*selects |
---|
| 559 | a list of :class:`~sqlalchemy.sql.expression.Select` instances. |
---|
| 560 | |
---|
| 561 | \**kwargs |
---|
| 562 | available keyword arguments are the same as those of |
---|
| 563 | :func:`~sqlalchemy.sql.expression.select`. |
---|
| 564 | |
---|
| 565 | """ |
---|
| 566 | return _compound_select('EXCEPT', *selects, **kwargs) |
---|
| 567 | |
---|
| 568 | def except_all(*selects, **kwargs): |
---|
| 569 | """Return an ``EXCEPT ALL`` of multiple selectables. |
---|
| 570 | |
---|
| 571 | The returned object is an instance of :class:`~sqlalchemy.sql.expression.CompoundSelect`. |
---|
| 572 | |
---|
| 573 | \*selects |
---|
| 574 | a list of :class:`~sqlalchemy.sql.expression.Select` instances. |
---|
| 575 | |
---|
| 576 | \**kwargs |
---|
| 577 | available keyword arguments are the same as those of |
---|
| 578 | :func:`~sqlalchemy.sql.expression.select`. |
---|
| 579 | |
---|
| 580 | """ |
---|
| 581 | return _compound_select('EXCEPT ALL', *selects, **kwargs) |
---|
| 582 | |
---|
| 583 | def intersect(*selects, **kwargs): |
---|
| 584 | """Return an ``INTERSECT`` of multiple selectables. |
---|
| 585 | |
---|
| 586 | The returned object is an instance of :class:`~sqlalchemy.sql.expression.CompoundSelect`. |
---|
| 587 | |
---|
| 588 | \*selects |
---|
| 589 | a list of :class:`~sqlalchemy.sql.expression.Select` instances. |
---|
| 590 | |
---|
| 591 | \**kwargs |
---|
| 592 | available keyword arguments are the same as those of |
---|
| 593 | :func:`~sqlalchemy.sql.expression.select`. |
---|
| 594 | |
---|
| 595 | """ |
---|
| 596 | return _compound_select('INTERSECT', *selects, **kwargs) |
---|
| 597 | |
---|
| 598 | def intersect_all(*selects, **kwargs): |
---|
| 599 | """Return an ``INTERSECT ALL`` of multiple selectables. |
---|
| 600 | |
---|
| 601 | The returned object is an instance of :class:`~sqlalchemy.sql.expression.CompoundSelect`. |
---|
| 602 | |
---|
| 603 | \*selects |
---|
| 604 | a list of :class:`~sqlalchemy.sql.expression.Select` instances. |
---|
| 605 | |
---|
| 606 | \**kwargs |
---|
| 607 | available keyword arguments are the same as those of |
---|
| 608 | :func:`~sqlalchemy.sql.expression.select`. |
---|
| 609 | |
---|
| 610 | """ |
---|
| 611 | return _compound_select('INTERSECT ALL', *selects, **kwargs) |
---|
| 612 | |
---|
| 613 | def alias(selectable, alias=None): |
---|
| 614 | """Return an :class:`~sqlalchemy.sql.expression.Alias` object. |
---|
| 615 | |
---|
| 616 | An ``Alias`` represents any :class:`~sqlalchemy.sql.expression.FromClause` with |
---|
| 617 | an alternate name assigned within SQL, typically using the ``AS`` |
---|
| 618 | clause when generated, e.g. ``SELECT * FROM table AS aliasname``. |
---|
| 619 | |
---|
| 620 | Similar functionality is available via the ``alias()`` method |
---|
| 621 | available on all ``FromClause`` subclasses. |
---|
| 622 | |
---|
| 623 | selectable |
---|
| 624 | any ``FromClause`` subclass, such as a table, select |
---|
| 625 | statement, etc.. |
---|
| 626 | |
---|
| 627 | alias |
---|
| 628 | string name to be assigned as the alias. If ``None``, a |
---|
| 629 | random name will be generated. |
---|
| 630 | |
---|
| 631 | """ |
---|
| 632 | return Alias(selectable, alias=alias) |
---|
| 633 | |
---|
| 634 | |
---|
| 635 | def literal(value, type_=None): |
---|
| 636 | """Return a literal clause, bound to a bind parameter. |
---|
| 637 | |
---|
| 638 | Literal clauses are created automatically when non- |
---|
| 639 | ``ClauseElement`` objects (such as strings, ints, dates, etc.) are |
---|
| 640 | used in a comparison operation with a |
---|
| 641 | :class:`~sqlalchemy.sql.expression._CompareMixin` subclass, such as a ``Column`` |
---|
| 642 | object. Use this function to force the generation of a literal |
---|
| 643 | clause, which will be created as a |
---|
| 644 | :class:`~sqlalchemy.sql.expression._BindParamClause` with a bound value. |
---|
| 645 | |
---|
| 646 | value |
---|
| 647 | the value to be bound. Can be any Python object supported by |
---|
| 648 | the underlying DB-API, or is translatable via the given type |
---|
| 649 | argument. |
---|
| 650 | |
---|
| 651 | type\_ |
---|
| 652 | an optional :class:`~sqlalchemy.types.TypeEngine` which will provide |
---|
| 653 | bind-parameter translation for this literal. |
---|
| 654 | |
---|
| 655 | """ |
---|
| 656 | return _BindParamClause(None, value, type_=type_, unique=True) |
---|
| 657 | |
---|
| 658 | def label(name, obj): |
---|
| 659 | """Return a :class:`~sqlalchemy.sql.expression._Label` object for the given :class:`~sqlalchemy.sql.expression.ColumnElement`. |
---|
| 660 | |
---|
| 661 | A label changes the name of an element in the columns clause of a |
---|
| 662 | ``SELECT`` statement, typically via the ``AS`` SQL keyword. |
---|
| 663 | |
---|
| 664 | This functionality is more conveniently available via the |
---|
| 665 | ``label()`` method on ``ColumnElement``. |
---|
| 666 | |
---|
| 667 | name |
---|
| 668 | label name |
---|
| 669 | |
---|
| 670 | obj |
---|
| 671 | a ``ColumnElement``. |
---|
| 672 | |
---|
| 673 | """ |
---|
| 674 | return _Label(name, obj) |
---|
| 675 | |
---|
| 676 | def column(text, type_=None): |
---|
| 677 | """Return a textual column clause, as would be in the columns clause of a ``SELECT`` statement. |
---|
| 678 | |
---|
| 679 | The object returned is an instance of :class:`~sqlalchemy.sql.expression.ColumnClause`, |
---|
| 680 | which represents the "syntactical" portion of the schema-level |
---|
| 681 | :class:`~sqlalchemy.schema.Column` object. |
---|
| 682 | |
---|
| 683 | text |
---|
| 684 | the name of the column. Quoting rules will be applied to the |
---|
| 685 | clause like any other column name. For textual column |
---|
| 686 | constructs that are not to be quoted, use the |
---|
| 687 | :func:`~sqlalchemy.sql.expression.literal_column` function. |
---|
| 688 | |
---|
| 689 | type\_ |
---|
| 690 | an optional :class:`~sqlalchemy.types.TypeEngine` object which will |
---|
| 691 | provide result-set translation for this column. |
---|
| 692 | |
---|
| 693 | """ |
---|
| 694 | return ColumnClause(text, type_=type_) |
---|
| 695 | |
---|
| 696 | def literal_column(text, type_=None): |
---|
| 697 | """Return a textual column expression, as would be in the columns |
---|
| 698 | clause of a ``SELECT`` statement. |
---|
| 699 | |
---|
| 700 | The object returned supports further expressions in the same way as any |
---|
| 701 | other column object, including comparison, math and string operations. |
---|
| 702 | The type\_ parameter is important to determine proper expression behavior |
---|
| 703 | (such as, '+' means string concatenation or numerical addition based on |
---|
| 704 | the type). |
---|
| 705 | |
---|
| 706 | text |
---|
| 707 | the text of the expression; can be any SQL expression. Quoting rules |
---|
| 708 | will not be applied. To specify a column-name expression which should |
---|
| 709 | be subject to quoting rules, use the |
---|
| 710 | :func:`~sqlalchemy.sql.expression.column` function. |
---|
| 711 | |
---|
| 712 | type\_ |
---|
| 713 | an optional :class:`~sqlalchemy.types.TypeEngine` object which will provide |
---|
| 714 | result-set translation and additional expression semantics for this |
---|
| 715 | column. If left as None the type will be NullType. |
---|
| 716 | |
---|
| 717 | """ |
---|
| 718 | return ColumnClause(text, type_=type_, is_literal=True) |
---|
| 719 | |
---|
| 720 | def table(name, *columns): |
---|
| 721 | """Return a :class:`~sqlalchemy.sql.expression.TableClause` object. |
---|
| 722 | |
---|
| 723 | This is a primitive version of the :class:`~sqlalchemy.schema.Table` object, |
---|
| 724 | which is a subclass of this object. |
---|
| 725 | |
---|
| 726 | """ |
---|
| 727 | return TableClause(name, *columns) |
---|
| 728 | |
---|
| 729 | def bindparam(key, value=None, shortname=None, type_=None, unique=False): |
---|
| 730 | """Create a bind parameter clause with the given key. |
---|
| 731 | |
---|
| 732 | value |
---|
| 733 | a default value for this bind parameter. a bindparam with a |
---|
| 734 | value is called a ``value-based bindparam``. |
---|
| 735 | |
---|
| 736 | type\_ |
---|
| 737 | a sqlalchemy.types.TypeEngine object indicating the type of this |
---|
| 738 | bind param, will invoke type-specific bind parameter processing |
---|
| 739 | |
---|
| 740 | shortname |
---|
| 741 | deprecated. |
---|
| 742 | |
---|
| 743 | unique |
---|
| 744 | if True, bind params sharing the same name will have their |
---|
| 745 | underlying ``key`` modified to a uniquely generated name. |
---|
| 746 | mostly useful with value-based bind params. |
---|
| 747 | |
---|
| 748 | """ |
---|
| 749 | if isinstance(key, ColumnClause): |
---|
| 750 | return _BindParamClause(key.name, value, type_=key.type, unique=unique, shortname=shortname) |
---|
| 751 | else: |
---|
| 752 | return _BindParamClause(key, value, type_=type_, unique=unique, shortname=shortname) |
---|
| 753 | |
---|
| 754 | def outparam(key, type_=None): |
---|
| 755 | """Create an 'OUT' parameter for usage in functions (stored procedures), for databases which support them. |
---|
| 756 | |
---|
| 757 | The ``outparam`` can be used like a regular function parameter. |
---|
| 758 | The "output" value will be available from the |
---|
| 759 | :class:`~sqlalchemy.engine.ResultProxy` object via its ``out_parameters`` |
---|
| 760 | attribute, which returns a dictionary containing the values. |
---|
| 761 | |
---|
| 762 | """ |
---|
| 763 | return _BindParamClause(key, None, type_=type_, unique=False, isoutparam=True) |
---|
| 764 | |
---|
| 765 | def text(text, bind=None, *args, **kwargs): |
---|
| 766 | """Create literal text to be inserted into a query. |
---|
| 767 | |
---|
| 768 | When constructing a query from a ``select()``, ``update()``, |
---|
| 769 | ``insert()`` or ``delete()``, using plain strings for argument |
---|
| 770 | values will usually result in text objects being created |
---|
| 771 | automatically. Use this function when creating textual clauses |
---|
| 772 | outside of other ``ClauseElement`` objects, or optionally wherever |
---|
| 773 | plain text is to be used. |
---|
| 774 | |
---|
| 775 | text |
---|
| 776 | the text of the SQL statement to be created. use ``:<param>`` |
---|
| 777 | to specify bind parameters; they will be compiled to their |
---|
| 778 | engine-specific format. |
---|
| 779 | |
---|
| 780 | bind |
---|
| 781 | an optional connection or engine to be used for this text query. |
---|
| 782 | |
---|
| 783 | autocommit=True |
---|
| 784 | indicates this SELECT statement modifies the database, and |
---|
| 785 | should be subject to autocommit behavior if no transaction |
---|
| 786 | has been started. |
---|
| 787 | |
---|
| 788 | bindparams |
---|
| 789 | a list of ``bindparam()`` instances which can be used to define |
---|
| 790 | the types and/or initial values for the bind parameters within |
---|
| 791 | the textual statement; the keynames of the bindparams must match |
---|
| 792 | those within the text of the statement. The types will be used |
---|
| 793 | for pre-processing on bind values. |
---|
| 794 | |
---|
| 795 | typemap |
---|
| 796 | a dictionary mapping the names of columns represented in the |
---|
| 797 | ``SELECT`` clause of the textual statement to type objects, |
---|
| 798 | which will be used to perform post-processing on columns within |
---|
| 799 | the result set (for textual statements that produce result |
---|
| 800 | sets). |
---|
| 801 | |
---|
| 802 | """ |
---|
| 803 | return _TextClause(text, bind=bind, *args, **kwargs) |
---|
| 804 | |
---|
| 805 | def null(): |
---|
| 806 | """Return a :class:`_Null` object, which compiles to ``NULL`` in a sql statement.""" |
---|
| 807 | |
---|
| 808 | return _Null() |
---|
| 809 | |
---|
| 810 | class _FunctionGenerator(object): |
---|
| 811 | """Generate :class:`Function` objects based on getattr calls.""" |
---|
| 812 | |
---|
| 813 | def __init__(self, **opts): |
---|
| 814 | self.__names = [] |
---|
| 815 | self.opts = opts |
---|
| 816 | |
---|
| 817 | def __getattr__(self, name): |
---|
| 818 | # passthru __ attributes; fixes pydoc |
---|
| 819 | if name.startswith('__'): |
---|
| 820 | try: |
---|
| 821 | return self.__dict__[name] |
---|
| 822 | except KeyError: |
---|
| 823 | raise AttributeError(name) |
---|
| 824 | |
---|
| 825 | elif name.endswith('_'): |
---|
| 826 | name = name[0:-1] |
---|
| 827 | f = _FunctionGenerator(**self.opts) |
---|
| 828 | f.__names = list(self.__names) + [name] |
---|
| 829 | return f |
---|
| 830 | |
---|
| 831 | def __call__(self, *c, **kwargs): |
---|
| 832 | o = self.opts.copy() |
---|
| 833 | o.update(kwargs) |
---|
| 834 | if len(self.__names) == 1: |
---|
| 835 | global functions |
---|
| 836 | if functions is None: |
---|
| 837 | from sqlalchemy.sql import functions |
---|
| 838 | func = getattr(functions, self.__names[-1].lower(), None) |
---|
| 839 | if func is not None: |
---|
| 840 | return func(*c, **o) |
---|
| 841 | |
---|
| 842 | return Function(self.__names[-1], packagenames=self.__names[0:-1], *c, **o) |
---|
| 843 | |
---|
| 844 | # "func" global - i.e. func.count() |
---|
| 845 | func = _FunctionGenerator() |
---|
| 846 | |
---|
| 847 | # "modifier" global - i.e. modifier.distinct |
---|
| 848 | # TODO: use UnaryExpression for this instead ? |
---|
| 849 | modifier = _FunctionGenerator(group=False) |
---|
| 850 | |
---|
| 851 | class _generated_label(unicode): |
---|
| 852 | """A unicode subclass used to identify dynamically generated names.""" |
---|
| 853 | |
---|
| 854 | def _escape_for_generated(x): |
---|
| 855 | if isinstance(x, _generated_label): |
---|
| 856 | return x |
---|
| 857 | else: |
---|
| 858 | return x.replace('%', '%%') |
---|
| 859 | |
---|
| 860 | def _clone(element): |
---|
| 861 | return element._clone() |
---|
| 862 | |
---|
| 863 | def _expand_cloned(elements): |
---|
| 864 | """expand the given set of ClauseElements to be the set of all 'cloned' predecessors.""" |
---|
| 865 | |
---|
| 866 | return itertools.chain(*[x._cloned_set for x in elements]) |
---|
| 867 | |
---|
| 868 | def _cloned_intersection(a, b): |
---|
| 869 | """return the intersection of sets a and b, counting |
---|
| 870 | any overlap between 'cloned' predecessors. |
---|
| 871 | |
---|
| 872 | The returned set is in terms of the enties present within 'a'. |
---|
| 873 | |
---|
| 874 | """ |
---|
| 875 | all_overlap = set(_expand_cloned(a)).intersection(_expand_cloned(b)) |
---|
| 876 | return set(elem for elem in a if all_overlap.intersection(elem._cloned_set)) |
---|
| 877 | |
---|
| 878 | def _compound_select(keyword, *selects, **kwargs): |
---|
| 879 | return CompoundSelect(keyword, *selects, **kwargs) |
---|
| 880 | |
---|
| 881 | def _is_literal(element): |
---|
| 882 | return not isinstance(element, Visitable) and not hasattr(element, '__clause_element__') |
---|
| 883 | |
---|
| 884 | def _from_objects(*elements): |
---|
| 885 | return itertools.chain(*[element._from_objects for element in elements]) |
---|
| 886 | |
---|
| 887 | def _labeled(element): |
---|
| 888 | if not hasattr(element, 'name'): |
---|
| 889 | return element.label(None) |
---|
| 890 | else: |
---|
| 891 | return element |
---|
| 892 | |
---|
| 893 | def _column_as_key(element): |
---|
| 894 | if isinstance(element, basestring): |
---|
| 895 | return element |
---|
| 896 | if hasattr(element, '__clause_element__'): |
---|
| 897 | element = element.__clause_element__() |
---|
| 898 | return element.key |
---|
| 899 | |
---|
| 900 | def _literal_as_text(element): |
---|
| 901 | if hasattr(element, '__clause_element__'): |
---|
| 902 | return element.__clause_element__() |
---|
| 903 | elif not isinstance(element, Visitable): |
---|
| 904 | return _TextClause(unicode(element)) |
---|
| 905 | else: |
---|
| 906 | return element |
---|
| 907 | |
---|
| 908 | def _clause_element_as_expr(element): |
---|
| 909 | if hasattr(element, '__clause_element__'): |
---|
| 910 | return element.__clause_element__() |
---|
| 911 | else: |
---|
| 912 | return element |
---|
| 913 | |
---|
| 914 | def _literal_as_column(element): |
---|
| 915 | if hasattr(element, '__clause_element__'): |
---|
| 916 | return element.__clause_element__() |
---|
| 917 | elif not isinstance(element, Visitable): |
---|
| 918 | return literal_column(str(element)) |
---|
| 919 | else: |
---|
| 920 | return element |
---|
| 921 | |
---|
| 922 | def _literal_as_binds(element, name=None, type_=None): |
---|
| 923 | if hasattr(element, '__clause_element__'): |
---|
| 924 | return element.__clause_element__() |
---|
| 925 | elif not isinstance(element, Visitable): |
---|
| 926 | if element is None: |
---|
| 927 | return null() |
---|
| 928 | else: |
---|
| 929 | return _BindParamClause(name, element, type_=type_, unique=True) |
---|
| 930 | else: |
---|
| 931 | return element |
---|
| 932 | |
---|
| 933 | def _no_literals(element): |
---|
| 934 | if hasattr(element, '__clause_element__'): |
---|
| 935 | return element.__clause_element__() |
---|
| 936 | elif not isinstance(element, Visitable): |
---|
| 937 | raise exc.ArgumentError("Ambiguous literal: %r. Use the 'text()' function " |
---|
| 938 | "to indicate a SQL expression literal, or 'literal()' to indicate a bound value." % element) |
---|
| 939 | else: |
---|
| 940 | return element |
---|
| 941 | |
---|
| 942 | def _corresponding_column_or_error(fromclause, column, require_embedded=False): |
---|
| 943 | c = fromclause.corresponding_column(column, require_embedded=require_embedded) |
---|
| 944 | if not c: |
---|
| 945 | raise exc.InvalidRequestError("Given column '%s', attached to table '%s', " |
---|
| 946 | "failed to locate a corresponding column from table '%s'" |
---|
| 947 | % (column, getattr(column, 'table', None), fromclause.description)) |
---|
| 948 | return c |
---|
| 949 | |
---|
| 950 | def is_column(col): |
---|
| 951 | """True if ``col`` is an instance of ``ColumnElement``.""" |
---|
| 952 | return isinstance(col, ColumnElement) |
---|
| 953 | |
---|
| 954 | |
---|
| 955 | class ClauseElement(Visitable): |
---|
| 956 | """Base class for elements of a programmatically constructed SQL expression.""" |
---|
| 957 | |
---|
| 958 | __visit_name__ = 'clause' |
---|
| 959 | |
---|
| 960 | _annotations = {} |
---|
| 961 | supports_execution = False |
---|
| 962 | _from_objects = [] |
---|
| 963 | |
---|
| 964 | def _clone(self): |
---|
| 965 | """Create a shallow copy of this ClauseElement. |
---|
| 966 | |
---|
| 967 | This method may be used by a generative API. Its also used as |
---|
| 968 | part of the "deep" copy afforded by a traversal that combines |
---|
| 969 | the _copy_internals() method. |
---|
| 970 | |
---|
| 971 | """ |
---|
| 972 | c = self.__class__.__new__(self.__class__) |
---|
| 973 | c.__dict__ = self.__dict__.copy() |
---|
| 974 | c.__dict__.pop('_cloned_set', None) |
---|
| 975 | |
---|
| 976 | # this is a marker that helps to "equate" clauses to each other |
---|
| 977 | # when a Select returns its list of FROM clauses. the cloning |
---|
| 978 | # process leaves around a lot of remnants of the previous clause |
---|
| 979 | # typically in the form of column expressions still attached to the |
---|
| 980 | # old table. |
---|
| 981 | c._is_clone_of = self |
---|
| 982 | |
---|
| 983 | return c |
---|
| 984 | |
---|
| 985 | @util.memoized_property |
---|
| 986 | def _cloned_set(self): |
---|
| 987 | """Return the set consisting all cloned anscestors of this ClauseElement. |
---|
| 988 | |
---|
| 989 | Includes this ClauseElement. This accessor tends to be used for |
---|
| 990 | FromClause objects to identify 'equivalent' FROM clauses, regardless |
---|
| 991 | of transformative operations. |
---|
| 992 | |
---|
| 993 | """ |
---|
| 994 | s = util.column_set() |
---|
| 995 | f = self |
---|
| 996 | while f is not None: |
---|
| 997 | s.add(f) |
---|
| 998 | f = getattr(f, '_is_clone_of', None) |
---|
| 999 | return s |
---|
| 1000 | |
---|
| 1001 | def __getstate__(self): |
---|
| 1002 | d = self.__dict__.copy() |
---|
| 1003 | d.pop('_is_clone_of', None) |
---|
| 1004 | return d |
---|
| 1005 | |
---|
| 1006 | def _annotate(self, values): |
---|
| 1007 | """return a copy of this ClauseElement with the given annotations dictionary.""" |
---|
| 1008 | |
---|
| 1009 | global Annotated |
---|
| 1010 | if Annotated is None: |
---|
| 1011 | from sqlalchemy.sql.util import Annotated |
---|
| 1012 | return Annotated(self, values) |
---|
| 1013 | |
---|
| 1014 | def _deannotate(self): |
---|
| 1015 | """return a copy of this ClauseElement with an empty annotations dictionary.""" |
---|
| 1016 | return self._clone() |
---|
| 1017 | |
---|
| 1018 | def unique_params(self, *optionaldict, **kwargs): |
---|
| 1019 | """Return a copy with ``bindparam()`` elments replaced. |
---|
| 1020 | |
---|
| 1021 | Same functionality as ``params()``, except adds `unique=True` |
---|
| 1022 | to affected bind parameters so that multiple statements can be |
---|
| 1023 | used. |
---|
| 1024 | |
---|
| 1025 | """ |
---|
| 1026 | return self._params(True, optionaldict, kwargs) |
---|
| 1027 | |
---|
| 1028 | def params(self, *optionaldict, **kwargs): |
---|
| 1029 | """Return a copy with ``bindparam()`` elments replaced. |
---|
| 1030 | |
---|
| 1031 | Returns a copy of this ClauseElement with ``bindparam()`` |
---|
| 1032 | elements replaced with values taken from the given dictionary:: |
---|
| 1033 | |
---|
| 1034 | >>> clause = column('x') + bindparam('foo') |
---|
| 1035 | >>> print clause.compile().params |
---|
| 1036 | {'foo':None} |
---|
| 1037 | >>> print clause.params({'foo':7}).compile().params |
---|
| 1038 | {'foo':7} |
---|
| 1039 | |
---|
| 1040 | """ |
---|
| 1041 | return self._params(False, optionaldict, kwargs) |
---|
| 1042 | |
---|
| 1043 | def _params(self, unique, optionaldict, kwargs): |
---|
| 1044 | if len(optionaldict) == 1: |
---|
| 1045 | kwargs.update(optionaldict[0]) |
---|
| 1046 | elif len(optionaldict) > 1: |
---|
| 1047 | raise exc.ArgumentError("params() takes zero or one positional dictionary argument") |
---|
| 1048 | |
---|
| 1049 | def visit_bindparam(bind): |
---|
| 1050 | if bind.key in kwargs: |
---|
| 1051 | bind.value = kwargs[bind.key] |
---|
| 1052 | if unique: |
---|
| 1053 | bind._convert_to_unique() |
---|
| 1054 | return cloned_traverse(self, {}, {'bindparam':visit_bindparam}) |
---|
| 1055 | |
---|
| 1056 | def compare(self, other): |
---|
| 1057 | """Compare this ClauseElement to the given ClauseElement. |
---|
| 1058 | |
---|
| 1059 | Subclasses should override the default behavior, which is a |
---|
| 1060 | straight identity comparison. |
---|
| 1061 | |
---|
| 1062 | """ |
---|
| 1063 | return self is other |
---|
| 1064 | |
---|
| 1065 | def _copy_internals(self, clone=_clone): |
---|
| 1066 | """Reassign internal elements to be clones of themselves. |
---|
| 1067 | |
---|
| 1068 | Called during a copy-and-traverse operation on newly |
---|
| 1069 | shallow-copied elements to create a deep copy. |
---|
| 1070 | |
---|
| 1071 | """ |
---|
| 1072 | pass |
---|
| 1073 | |
---|
| 1074 | def get_children(self, **kwargs): |
---|
| 1075 | """Return immediate child elements of this ``ClauseElement``. |
---|
| 1076 | |
---|
| 1077 | This is used for visit traversal. |
---|
| 1078 | |
---|
| 1079 | \**kwargs may contain flags that change the collection that is |
---|
| 1080 | returned, for example to return a subset of items in order to |
---|
| 1081 | cut down on larger traversals, or to return child items from a |
---|
| 1082 | different context (such as schema-level collections instead of |
---|
| 1083 | clause-level). |
---|
| 1084 | |
---|
| 1085 | """ |
---|
| 1086 | return [] |
---|
| 1087 | |
---|
| 1088 | def self_group(self, against=None): |
---|
| 1089 | return self |
---|
| 1090 | |
---|
| 1091 | @property |
---|
| 1092 | def bind(self): |
---|
| 1093 | """Returns the Engine or Connection to which this ClauseElement is bound, or None if none found.""" |
---|
| 1094 | |
---|
| 1095 | try: |
---|
| 1096 | if self._bind is not None: |
---|
| 1097 | return self._bind |
---|
| 1098 | except AttributeError: |
---|
| 1099 | pass |
---|
| 1100 | for f in _from_objects(self): |
---|
| 1101 | if f is self: |
---|
| 1102 | continue |
---|
| 1103 | engine = f.bind |
---|
| 1104 | if engine is not None: |
---|
| 1105 | return engine |
---|
| 1106 | else: |
---|
| 1107 | return None |
---|
| 1108 | |
---|
| 1109 | def execute(self, *multiparams, **params): |
---|
| 1110 | """Compile and execute this ``ClauseElement``.""" |
---|
| 1111 | |
---|
| 1112 | e = self.bind |
---|
| 1113 | if e is None: |
---|
| 1114 | label = getattr(self, 'description', self.__class__.__name__) |
---|
| 1115 | msg = ('This %s is not bound and does not support direct ' |
---|
| 1116 | 'execution. Supply this statement to a Connection or ' |
---|
| 1117 | 'Engine for execution. Or, assign a bind to the statement ' |
---|
| 1118 | 'or the Metadata of its underlying tables to enable ' |
---|
| 1119 | 'implicit execution via this method.' % label) |
---|
| 1120 | raise exc.UnboundExecutionError(msg) |
---|
| 1121 | return e._execute_clauseelement(self, multiparams, params) |
---|
| 1122 | |
---|
| 1123 | def scalar(self, *multiparams, **params): |
---|
| 1124 | """Compile and execute this ``ClauseElement``, returning the result's scalar representation.""" |
---|
| 1125 | |
---|
| 1126 | return self.execute(*multiparams, **params).scalar() |
---|
| 1127 | |
---|
| 1128 | def compile(self, bind=None, column_keys=None, compiler=None, dialect=None, inline=False): |
---|
| 1129 | """Compile this SQL expression. |
---|
| 1130 | |
---|
| 1131 | The return value is a :class:`~sqlalchemy.engine.Compiled` object. |
---|
| 1132 | Calling `str()` or `unicode()` on the returned value will yield |
---|
| 1133 | a string representation of the result. The :class:`~sqlalchemy.engine.Compiled` |
---|
| 1134 | object also can return a dictionary of bind parameter names and |
---|
| 1135 | values using the `params` accessor. |
---|
| 1136 | |
---|
| 1137 | :param bind: An ``Engine`` or ``Connection`` from which a |
---|
| 1138 | ``Compiled`` will be acquired. This argument |
---|
| 1139 | takes precedence over this ``ClauseElement``'s |
---|
| 1140 | bound engine, if any. |
---|
| 1141 | |
---|
| 1142 | :param column_keys: Used for INSERT and UPDATE statements, a list of |
---|
| 1143 | column names which should be present in the VALUES clause |
---|
| 1144 | of the compiled statement. If ``None``, all columns |
---|
| 1145 | from the target table object are rendered. |
---|
| 1146 | |
---|
| 1147 | :param compiler: A ``Compiled`` instance which will be used to compile |
---|
| 1148 | this expression. This argument takes precedence |
---|
| 1149 | over the `bind` and `dialect` arguments as well as |
---|
| 1150 | this ``ClauseElement``'s bound engine, if |
---|
| 1151 | any. |
---|
| 1152 | |
---|
| 1153 | :param dialect: A ``Dialect`` instance frmo which a ``Compiled`` |
---|
| 1154 | will be acquired. This argument takes precedence |
---|
| 1155 | over the `bind` argument as well as this |
---|
| 1156 | ``ClauseElement``'s bound engine, if any. |
---|
| 1157 | |
---|
| 1158 | :param inline: Used for INSERT statements, for a dialect which does |
---|
| 1159 | not support inline retrieval of newly generated |
---|
| 1160 | primary key columns, will force the expression used |
---|
| 1161 | to create the new primary key value to be rendered |
---|
| 1162 | inline within the INSERT statement's VALUES clause. |
---|
| 1163 | This typically refers to Sequence execution but |
---|
| 1164 | may also refer to any server-side default generation |
---|
| 1165 | function associated with a primary key `Column`. |
---|
| 1166 | |
---|
| 1167 | """ |
---|
| 1168 | if compiler is None: |
---|
| 1169 | if dialect is not None: |
---|
| 1170 | compiler = dialect.statement_compiler(dialect, self, column_keys=column_keys, inline=inline) |
---|
| 1171 | elif bind is not None: |
---|
| 1172 | compiler = bind.statement_compiler(self, column_keys=column_keys, inline=inline) |
---|
| 1173 | elif self.bind is not None: |
---|
| 1174 | compiler = self.bind.statement_compiler(self, column_keys=column_keys, inline=inline) |
---|
| 1175 | else: |
---|
| 1176 | global DefaultDialect |
---|
| 1177 | if DefaultDialect is None: |
---|
| 1178 | from sqlalchemy.engine.default import DefaultDialect |
---|
| 1179 | dialect = DefaultDialect() |
---|
| 1180 | compiler = dialect.statement_compiler(dialect, self, column_keys=column_keys, inline=inline) |
---|
| 1181 | compiler.compile() |
---|
| 1182 | return compiler |
---|
| 1183 | |
---|
| 1184 | def __str__(self): |
---|
| 1185 | return unicode(self.compile()).encode('ascii', 'backslashreplace') |
---|
| 1186 | |
---|
| 1187 | def __and__(self, other): |
---|
| 1188 | return and_(self, other) |
---|
| 1189 | |
---|
| 1190 | def __or__(self, other): |
---|
| 1191 | return or_(self, other) |
---|
| 1192 | |
---|
| 1193 | def __invert__(self): |
---|
| 1194 | return self._negate() |
---|
| 1195 | |
---|
| 1196 | def _negate(self): |
---|
| 1197 | if hasattr(self, 'negation_clause'): |
---|
| 1198 | return self.negation_clause |
---|
| 1199 | else: |
---|
| 1200 | return _UnaryExpression(self.self_group(against=operators.inv), operator=operators.inv, negate=None) |
---|
| 1201 | |
---|
| 1202 | def __repr__(self): |
---|
| 1203 | friendly = getattr(self, 'description', None) |
---|
| 1204 | if friendly is None: |
---|
| 1205 | return object.__repr__(self) |
---|
| 1206 | else: |
---|
| 1207 | return '<%s.%s at 0x%x; %s>' % ( |
---|
| 1208 | self.__module__, self.__class__.__name__, id(self), friendly) |
---|
| 1209 | |
---|
| 1210 | |
---|
| 1211 | class _Immutable(object): |
---|
| 1212 | """mark a ClauseElement as 'immutable' when expressions are cloned.""" |
---|
| 1213 | |
---|
| 1214 | def _clone(self): |
---|
| 1215 | return self |
---|
| 1216 | |
---|
| 1217 | class Operators(object): |
---|
| 1218 | def __and__(self, other): |
---|
| 1219 | return self.operate(operators.and_, other) |
---|
| 1220 | |
---|
| 1221 | def __or__(self, other): |
---|
| 1222 | return self.operate(operators.or_, other) |
---|
| 1223 | |
---|
| 1224 | def __invert__(self): |
---|
| 1225 | return self.operate(operators.inv) |
---|
| 1226 | |
---|
| 1227 | def op(self, opstring): |
---|
| 1228 | def op(b): |
---|
| 1229 | return self.operate(operators.op, opstring, b) |
---|
| 1230 | return op |
---|
| 1231 | |
---|
| 1232 | def operate(self, op, *other, **kwargs): |
---|
| 1233 | raise NotImplementedError(str(op)) |
---|
| 1234 | |
---|
| 1235 | def reverse_operate(self, op, other, **kwargs): |
---|
| 1236 | raise NotImplementedError(str(op)) |
---|
| 1237 | |
---|
| 1238 | class ColumnOperators(Operators): |
---|
| 1239 | """Defines comparison and math operations.""" |
---|
| 1240 | |
---|
| 1241 | timetuple = None |
---|
| 1242 | """Hack, allows datetime objects to be compared on the LHS.""" |
---|
| 1243 | |
---|
| 1244 | def __lt__(self, other): |
---|
| 1245 | return self.operate(operators.lt, other) |
---|
| 1246 | |
---|
| 1247 | def __le__(self, other): |
---|
| 1248 | return self.operate(operators.le, other) |
---|
| 1249 | |
---|
| 1250 | __hash__ = Operators.__hash__ |
---|
| 1251 | |
---|
| 1252 | def __eq__(self, other): |
---|
| 1253 | return self.operate(operators.eq, other) |
---|
| 1254 | |
---|
| 1255 | def __ne__(self, other): |
---|
| 1256 | return self.operate(operators.ne, other) |
---|
| 1257 | |
---|
| 1258 | def __gt__(self, other): |
---|
| 1259 | return self.operate(operators.gt, other) |
---|
| 1260 | |
---|
| 1261 | def __ge__(self, other): |
---|
| 1262 | return self.operate(operators.ge, other) |
---|
| 1263 | |
---|
| 1264 | def concat(self, other): |
---|
| 1265 | return self.operate(operators.concat_op, other) |
---|
| 1266 | |
---|
| 1267 | def like(self, other, escape=None): |
---|
| 1268 | return self.operate(operators.like_op, other, escape=escape) |
---|
| 1269 | |
---|
| 1270 | def ilike(self, other, escape=None): |
---|
| 1271 | return self.operate(operators.ilike_op, other, escape=escape) |
---|
| 1272 | |
---|
| 1273 | def in_(self, other): |
---|
| 1274 | return self.operate(operators.in_op, other) |
---|
| 1275 | |
---|
| 1276 | def startswith(self, other, **kwargs): |
---|
| 1277 | return self.operate(operators.startswith_op, other, **kwargs) |
---|
| 1278 | |
---|
| 1279 | def endswith(self, other, **kwargs): |
---|
| 1280 | return self.operate(operators.endswith_op, other, **kwargs) |
---|
| 1281 | |
---|
| 1282 | def contains(self, other, **kwargs): |
---|
| 1283 | return self.operate(operators.contains_op, other, **kwargs) |
---|
| 1284 | |
---|
| 1285 | def match(self, other, **kwargs): |
---|
| 1286 | return self.operate(operators.match_op, other, **kwargs) |
---|
| 1287 | |
---|
| 1288 | def desc(self): |
---|
| 1289 | return self.operate(operators.desc_op) |
---|
| 1290 | |
---|
| 1291 | def asc(self): |
---|
| 1292 | return self.operate(operators.asc_op) |
---|
| 1293 | |
---|
| 1294 | def collate(self, collation): |
---|
| 1295 | return self.operate(operators.collate, collation) |
---|
| 1296 | |
---|
| 1297 | def __radd__(self, other): |
---|
| 1298 | return self.reverse_operate(operators.add, other) |
---|
| 1299 | |
---|
| 1300 | def __rsub__(self, other): |
---|
| 1301 | return self.reverse_operate(operators.sub, other) |
---|
| 1302 | |
---|
| 1303 | def __rmul__(self, other): |
---|
| 1304 | return self.reverse_operate(operators.mul, other) |
---|
| 1305 | |
---|
| 1306 | def __rdiv__(self, other): |
---|
| 1307 | return self.reverse_operate(operators.div, other) |
---|
| 1308 | |
---|
| 1309 | def between(self, cleft, cright): |
---|
| 1310 | return self.operate(operators.between_op, cleft, cright) |
---|
| 1311 | |
---|
| 1312 | def distinct(self): |
---|
| 1313 | return self.operate(operators.distinct_op) |
---|
| 1314 | |
---|
| 1315 | def __add__(self, other): |
---|
| 1316 | return self.operate(operators.add, other) |
---|
| 1317 | |
---|
| 1318 | def __sub__(self, other): |
---|
| 1319 | return self.operate(operators.sub, other) |
---|
| 1320 | |
---|
| 1321 | def __mul__(self, other): |
---|
| 1322 | return self.operate(operators.mul, other) |
---|
| 1323 | |
---|
| 1324 | def __div__(self, other): |
---|
| 1325 | return self.operate(operators.div, other) |
---|
| 1326 | |
---|
| 1327 | def __mod__(self, other): |
---|
| 1328 | return self.operate(operators.mod, other) |
---|
| 1329 | |
---|
| 1330 | def __truediv__(self, other): |
---|
| 1331 | return self.operate(operators.truediv, other) |
---|
| 1332 | |
---|
| 1333 | class _CompareMixin(ColumnOperators): |
---|
| 1334 | """Defines comparison and math operations for ``ClauseElement`` instances.""" |
---|
| 1335 | |
---|
| 1336 | def __compare(self, op, obj, negate=None, reverse=False, **kwargs): |
---|
| 1337 | if obj is None or isinstance(obj, _Null): |
---|
| 1338 | if op == operators.eq: |
---|
| 1339 | return _BinaryExpression(self, null(), operators.is_, negate=operators.isnot) |
---|
| 1340 | elif op == operators.ne: |
---|
| 1341 | return _BinaryExpression(self, null(), operators.isnot, negate=operators.is_) |
---|
| 1342 | else: |
---|
| 1343 | raise exc.ArgumentError("Only '='/'!=' operators can be used with NULL") |
---|
| 1344 | else: |
---|
| 1345 | obj = self._check_literal(obj) |
---|
| 1346 | |
---|
| 1347 | if reverse: |
---|
| 1348 | return _BinaryExpression(obj, self, op, type_=sqltypes.Boolean, negate=negate, modifiers=kwargs) |
---|
| 1349 | else: |
---|
| 1350 | return _BinaryExpression(self, obj, op, type_=sqltypes.Boolean, negate=negate, modifiers=kwargs) |
---|
| 1351 | |
---|
| 1352 | def __operate(self, op, obj, reverse=False): |
---|
| 1353 | obj = self._check_literal(obj) |
---|
| 1354 | |
---|
| 1355 | type_ = self._compare_type(obj) |
---|
| 1356 | |
---|
| 1357 | if reverse: |
---|
| 1358 | return _BinaryExpression(obj, self, type_.adapt_operator(op), type_=type_) |
---|
| 1359 | else: |
---|
| 1360 | return _BinaryExpression(self, obj, type_.adapt_operator(op), type_=type_) |
---|
| 1361 | |
---|
| 1362 | # a mapping of operators with the method they use, along with their negated |
---|
| 1363 | # operator for comparison operators |
---|
| 1364 | operators = { |
---|
| 1365 | operators.add : (__operate,), |
---|
| 1366 | operators.mul : (__operate,), |
---|
| 1367 | operators.sub : (__operate,), |
---|
| 1368 | operators.div : (__operate,), |
---|
| 1369 | operators.mod : (__operate,), |
---|
| 1370 | operators.truediv : (__operate,), |
---|
| 1371 | operators.lt : (__compare, operators.ge), |
---|
| 1372 | operators.le : (__compare, operators.gt), |
---|
| 1373 | operators.ne : (__compare, operators.eq), |
---|
| 1374 | operators.gt : (__compare, operators.le), |
---|
| 1375 | operators.ge : (__compare, operators.lt), |
---|
| 1376 | operators.eq : (__compare, operators.ne), |
---|
| 1377 | operators.like_op : (__compare, operators.notlike_op), |
---|
| 1378 | operators.ilike_op : (__compare, operators.notilike_op), |
---|
| 1379 | } |
---|
| 1380 | |
---|
| 1381 | def operate(self, op, *other, **kwargs): |
---|
| 1382 | o = _CompareMixin.operators[op] |
---|
| 1383 | return o[0](self, op, other[0], *o[1:], **kwargs) |
---|
| 1384 | |
---|
| 1385 | def reverse_operate(self, op, other, **kwargs): |
---|
| 1386 | o = _CompareMixin.operators[op] |
---|
| 1387 | return o[0](self, op, other, reverse=True, *o[1:], **kwargs) |
---|
| 1388 | |
---|
| 1389 | def in_(self, other): |
---|
| 1390 | return self._in_impl(operators.in_op, operators.notin_op, other) |
---|
| 1391 | |
---|
| 1392 | def _in_impl(self, op, negate_op, seq_or_selectable): |
---|
| 1393 | seq_or_selectable = _clause_element_as_expr(seq_or_selectable) |
---|
| 1394 | |
---|
| 1395 | if isinstance(seq_or_selectable, _ScalarSelect): |
---|
| 1396 | return self.__compare( op, seq_or_selectable, negate=negate_op) |
---|
| 1397 | |
---|
| 1398 | elif isinstance(seq_or_selectable, _SelectBaseMixin): |
---|
| 1399 | # TODO: if we ever want to support (x, y, z) IN (select x, y, z from table), |
---|
| 1400 | # we would need a multi-column version of as_scalar() to produce a multi- |
---|
| 1401 | # column selectable that does not export itself as a FROM clause |
---|
| 1402 | return self.__compare( op, seq_or_selectable.as_scalar(), negate=negate_op) |
---|
| 1403 | |
---|
| 1404 | elif isinstance(seq_or_selectable, Selectable): |
---|
| 1405 | return self.__compare( op, seq_or_selectable, negate=negate_op) |
---|
| 1406 | |
---|
| 1407 | # Handle non selectable arguments as sequences |
---|
| 1408 | args = [] |
---|
| 1409 | for o in seq_or_selectable: |
---|
| 1410 | if not _is_literal(o): |
---|
| 1411 | if not isinstance( o, _CompareMixin): |
---|
| 1412 | raise exc.InvalidRequestError( |
---|
| 1413 | "in() function accepts either a list of non-selectable values, or a selectable: %r" % o) |
---|
| 1414 | else: |
---|
| 1415 | o = self._bind_param(o) |
---|
| 1416 | args.append(o) |
---|
| 1417 | |
---|
| 1418 | if len(args) == 0: |
---|
| 1419 | # Special case handling for empty IN's, behave like comparison against zero row selectable |
---|
| 1420 | return self != self |
---|
| 1421 | |
---|
| 1422 | return self.__compare(op, ClauseList(*args).self_group(against=op), negate=negate_op) |
---|
| 1423 | |
---|
| 1424 | def startswith(self, other, escape=None): |
---|
| 1425 | """Produce the clause ``LIKE '<other>%'``""" |
---|
| 1426 | |
---|
| 1427 | # use __radd__ to force string concat behavior |
---|
| 1428 | return self.__compare( |
---|
| 1429 | operators.like_op, |
---|
| 1430 | literal_column("'%'", type_=sqltypes.String).__radd__(self._check_literal(other)), |
---|
| 1431 | escape=escape) |
---|
| 1432 | |
---|
| 1433 | def endswith(self, other, escape=None): |
---|
| 1434 | """Produce the clause ``LIKE '%<other>'``""" |
---|
| 1435 | |
---|
| 1436 | return self.__compare( |
---|
| 1437 | operators.like_op, |
---|
| 1438 | literal_column("'%'", type_=sqltypes.String) + self._check_literal(other), |
---|
| 1439 | escape=escape) |
---|
| 1440 | |
---|
| 1441 | def contains(self, other, escape=None): |
---|
| 1442 | """Produce the clause ``LIKE '%<other>%'``""" |
---|
| 1443 | |
---|
| 1444 | return self.__compare( |
---|
| 1445 | operators.like_op, |
---|
| 1446 | literal_column("'%'", type_=sqltypes.String) + |
---|
| 1447 | self._check_literal(other) + |
---|
| 1448 | literal_column("'%'", type_=sqltypes.String), |
---|
| 1449 | escape=escape) |
---|
| 1450 | |
---|
| 1451 | def match(self, other): |
---|
| 1452 | """Produce a MATCH clause, i.e. ``MATCH '<other>'`` |
---|
| 1453 | |
---|
| 1454 | The allowed contents of ``other`` are database backend specific. |
---|
| 1455 | |
---|
| 1456 | """ |
---|
| 1457 | return self.__compare(operators.match_op, self._check_literal(other)) |
---|
| 1458 | |
---|
| 1459 | def label(self, name): |
---|
| 1460 | """Produce a column label, i.e. ``<columnname> AS <name>``. |
---|
| 1461 | |
---|
| 1462 | if 'name' is None, an anonymous label name will be generated. |
---|
| 1463 | |
---|
| 1464 | """ |
---|
| 1465 | return _Label(name, self, self.type) |
---|
| 1466 | |
---|
| 1467 | def desc(self): |
---|
| 1468 | """Produce a DESC clause, i.e. ``<columnname> DESC``""" |
---|
| 1469 | |
---|
| 1470 | return desc(self) |
---|
| 1471 | |
---|
| 1472 | def asc(self): |
---|
| 1473 | """Produce a ASC clause, i.e. ``<columnname> ASC``""" |
---|
| 1474 | |
---|
| 1475 | return asc(self) |
---|
| 1476 | |
---|
| 1477 | def distinct(self): |
---|
| 1478 | """Produce a DISTINCT clause, i.e. ``DISTINCT <columnname>``""" |
---|
| 1479 | return _UnaryExpression(self, operator=operators.distinct_op, type_=self.type) |
---|
| 1480 | |
---|
| 1481 | def between(self, cleft, cright): |
---|
| 1482 | """Produce a BETWEEN clause, i.e. ``<column> BETWEEN <cleft> AND <cright>``""" |
---|
| 1483 | |
---|
| 1484 | return _BinaryExpression( |
---|
| 1485 | self, |
---|
| 1486 | ClauseList( |
---|
| 1487 | self._check_literal(cleft), |
---|
| 1488 | self._check_literal(cright), |
---|
| 1489 | operator=operators.and_, |
---|
| 1490 | group=False), |
---|
| 1491 | operators.between_op) |
---|
| 1492 | |
---|
| 1493 | def collate(self, collation): |
---|
| 1494 | """Produce a COLLATE clause, i.e. ``<column> COLLATE utf8_bin``""" |
---|
| 1495 | |
---|
| 1496 | return collate(self, collation) |
---|
| 1497 | |
---|
| 1498 | def op(self, operator): |
---|
| 1499 | """produce a generic operator function. |
---|
| 1500 | |
---|
| 1501 | e.g.:: |
---|
| 1502 | |
---|
| 1503 | somecolumn.op("*")(5) |
---|
| 1504 | |
---|
| 1505 | produces:: |
---|
| 1506 | |
---|
| 1507 | somecolumn * 5 |
---|
| 1508 | |
---|
| 1509 | operator |
---|
| 1510 | a string which will be output as the infix operator between |
---|
| 1511 | this ``ClauseElement`` and the expression passed to the |
---|
| 1512 | generated function. |
---|
| 1513 | |
---|
| 1514 | """ |
---|
| 1515 | return lambda other: self.__operate(operator, other) |
---|
| 1516 | |
---|
| 1517 | def _bind_param(self, obj): |
---|
| 1518 | return _BindParamClause(None, obj, type_=self.type, unique=True) |
---|
| 1519 | |
---|
| 1520 | def _check_literal(self, other): |
---|
| 1521 | if isinstance(other, _BindParamClause) and isinstance(other.type, sqltypes.NullType): |
---|
| 1522 | other.type = self.type |
---|
| 1523 | return other |
---|
| 1524 | elif hasattr(other, '__clause_element__'): |
---|
| 1525 | return other.__clause_element__() |
---|
| 1526 | elif not isinstance(other, ClauseElement): |
---|
| 1527 | return self._bind_param(other) |
---|
| 1528 | elif isinstance(other, (_SelectBaseMixin, Alias)): |
---|
| 1529 | return other.as_scalar() |
---|
| 1530 | else: |
---|
| 1531 | return other |
---|
| 1532 | |
---|
| 1533 | def _compare_type(self, obj): |
---|
| 1534 | """Allow subclasses to override the type used in constructing |
---|
| 1535 | ``_BinaryExpression`` objects. |
---|
| 1536 | |
---|
| 1537 | Default return value is the type of the given object. |
---|
| 1538 | |
---|
| 1539 | """ |
---|
| 1540 | return obj.type |
---|
| 1541 | |
---|
| 1542 | class ColumnElement(ClauseElement, _CompareMixin): |
---|
| 1543 | """Represent an element that is usable within the "column clause" portion of a ``SELECT`` statement. |
---|
| 1544 | |
---|
| 1545 | This includes columns associated with tables, aliases, and |
---|
| 1546 | subqueries, expressions, function calls, SQL keywords such as |
---|
| 1547 | ``NULL``, literals, etc. ``ColumnElement`` is the ultimate base |
---|
| 1548 | class for all such elements. |
---|
| 1549 | |
---|
| 1550 | ``ColumnElement`` supports the ability to be a *proxy* element, |
---|
| 1551 | which indicates that the ``ColumnElement`` may be associated with |
---|
| 1552 | a ``Selectable`` which was derived from another ``Selectable``. |
---|
| 1553 | An example of a "derived" ``Selectable`` is an ``Alias`` of a |
---|
| 1554 | ``Table``. |
---|
| 1555 | |
---|
| 1556 | A ``ColumnElement``, by subclassing the ``_CompareMixin`` mixin |
---|
| 1557 | class, provides the ability to generate new ``ClauseElement`` |
---|
| 1558 | objects using Python expressions. See the ``_CompareMixin`` |
---|
| 1559 | docstring for more details. |
---|
| 1560 | |
---|
| 1561 | """ |
---|
| 1562 | |
---|
| 1563 | __visit_name__ = 'column' |
---|
| 1564 | primary_key = False |
---|
| 1565 | foreign_keys = [] |
---|
| 1566 | quote = None |
---|
| 1567 | _label = None |
---|
| 1568 | |
---|
| 1569 | @property |
---|
| 1570 | def _select_iterable(self): |
---|
| 1571 | return (self, ) |
---|
| 1572 | |
---|
| 1573 | @util.memoized_property |
---|
| 1574 | def base_columns(self): |
---|
| 1575 | return util.column_set(c for c in self.proxy_set |
---|
| 1576 | if not hasattr(c, 'proxies')) |
---|
| 1577 | |
---|
| 1578 | @util.memoized_property |
---|
| 1579 | def proxy_set(self): |
---|
| 1580 | s = util.column_set([self]) |
---|
| 1581 | if hasattr(self, 'proxies'): |
---|
| 1582 | for c in self.proxies: |
---|
| 1583 | s.update(c.proxy_set) |
---|
| 1584 | return s |
---|
| 1585 | |
---|
| 1586 | def shares_lineage(self, othercolumn): |
---|
| 1587 | """Return True if the given ``ColumnElement`` has a common ancestor to this ``ColumnElement``.""" |
---|
| 1588 | |
---|
| 1589 | return bool(self.proxy_set.intersection(othercolumn.proxy_set)) |
---|
| 1590 | |
---|
| 1591 | def _make_proxy(self, selectable, name=None): |
---|
| 1592 | """Create a new ``ColumnElement`` representing this |
---|
| 1593 | ``ColumnElement`` as it appears in the select list of a |
---|
| 1594 | descending selectable. |
---|
| 1595 | |
---|
| 1596 | """ |
---|
| 1597 | |
---|
| 1598 | if name: |
---|
| 1599 | co = ColumnClause(name, selectable, type_=getattr(self, 'type', None)) |
---|
| 1600 | else: |
---|
| 1601 | name = str(self) |
---|
| 1602 | co = ColumnClause(self.anon_label, selectable, type_=getattr(self, 'type', None)) |
---|
| 1603 | |
---|
| 1604 | co.proxies = [self] |
---|
| 1605 | selectable.columns[name] = co |
---|
| 1606 | return co |
---|
| 1607 | |
---|
| 1608 | @util.memoized_property |
---|
| 1609 | def anon_label(self): |
---|
| 1610 | """provides a constant 'anonymous label' for this ColumnElement. |
---|
| 1611 | |
---|
| 1612 | This is a label() expression which will be named at compile time. |
---|
| 1613 | The same label() is returned each time anon_label is called so |
---|
| 1614 | that expressions can reference anon_label multiple times, producing |
---|
| 1615 | the same label name at compile time. |
---|
| 1616 | |
---|
| 1617 | the compiler uses this function automatically at compile time |
---|
| 1618 | for expressions that are known to be 'unnamed' like binary |
---|
| 1619 | expressions and function calls. |
---|
| 1620 | |
---|
| 1621 | """ |
---|
| 1622 | return _generated_label("%%(%d %s)s" % (id(self), getattr(self, 'name', 'anon'))) |
---|
| 1623 | |
---|
| 1624 | class ColumnCollection(util.OrderedProperties): |
---|
| 1625 | """An ordered dictionary that stores a list of ColumnElement |
---|
| 1626 | instances. |
---|
| 1627 | |
---|
| 1628 | Overrides the ``__eq__()`` method to produce SQL clauses between |
---|
| 1629 | sets of correlated columns. |
---|
| 1630 | |
---|
| 1631 | """ |
---|
| 1632 | |
---|
| 1633 | def __init__(self, *cols): |
---|
| 1634 | super(ColumnCollection, self).__init__() |
---|
| 1635 | [self.add(c) for c in cols] |
---|
| 1636 | |
---|
| 1637 | def __str__(self): |
---|
| 1638 | return repr([str(c) for c in self]) |
---|
| 1639 | |
---|
| 1640 | def replace(self, column): |
---|
| 1641 | """add the given column to this collection, removing unaliased versions of this column |
---|
| 1642 | as well as existing columns with the same key. |
---|
| 1643 | |
---|
| 1644 | e.g.:: |
---|
| 1645 | |
---|
| 1646 | t = Table('sometable', metadata, Column('col1', Integer)) |
---|
| 1647 | t.columns.replace(Column('col1', Integer, key='columnone')) |
---|
| 1648 | |
---|
| 1649 | will remove the original 'col1' from the collection, and add |
---|
| 1650 | the new column under the name 'columnname'. |
---|
| 1651 | |
---|
| 1652 | Used by schema.Column to override columns during table reflection. |
---|
| 1653 | |
---|
| 1654 | """ |
---|
| 1655 | if column.name in self and column.key != column.name: |
---|
| 1656 | other = self[column.name] |
---|
| 1657 | if other.name == other.key: |
---|
| 1658 | del self[other.name] |
---|
| 1659 | util.OrderedProperties.__setitem__(self, column.key, column) |
---|
| 1660 | |
---|
| 1661 | def add(self, column): |
---|
| 1662 | """Add a column to this collection. |
---|
| 1663 | |
---|
| 1664 | The key attribute of the column will be used as the hash key |
---|
| 1665 | for this dictionary. |
---|
| 1666 | |
---|
| 1667 | """ |
---|
| 1668 | self[column.key] = column |
---|
| 1669 | |
---|
| 1670 | def __setitem__(self, key, value): |
---|
| 1671 | if key in self: |
---|
| 1672 | # this warning is primarily to catch select() statements which have conflicting |
---|
| 1673 | # column names in their exported columns collection |
---|
| 1674 | existing = self[key] |
---|
| 1675 | if not existing.shares_lineage(value): |
---|
| 1676 | table = getattr(existing, 'table', None) and existing.table.description |
---|
| 1677 | util.warn(("Column %r on table %r being replaced by another " |
---|
| 1678 | "column with the same key. Consider use_labels " |
---|
| 1679 | "for select() statements.") % (key, table)) |
---|
| 1680 | util.OrderedProperties.__setitem__(self, key, value) |
---|
| 1681 | |
---|
| 1682 | def remove(self, column): |
---|
| 1683 | del self[column.key] |
---|
| 1684 | |
---|
| 1685 | def extend(self, iter): |
---|
| 1686 | for c in iter: |
---|
| 1687 | self.add(c) |
---|
| 1688 | |
---|
| 1689 | __hash__ = None |
---|
| 1690 | |
---|
| 1691 | def __eq__(self, other): |
---|
| 1692 | l = [] |
---|
| 1693 | for c in other: |
---|
| 1694 | for local in self: |
---|
| 1695 | if c.shares_lineage(local): |
---|
| 1696 | l.append(c==local) |
---|
| 1697 | return and_(*l) |
---|
| 1698 | |
---|
| 1699 | def __contains__(self, other): |
---|
| 1700 | if not isinstance(other, basestring): |
---|
| 1701 | raise exc.ArgumentError("__contains__ requires a string argument") |
---|
| 1702 | return util.OrderedProperties.__contains__(self, other) |
---|
| 1703 | |
---|
| 1704 | def contains_column(self, col): |
---|
| 1705 | # have to use a Set here, because it will compare the identity |
---|
| 1706 | # of the column, not just using "==" for comparison which will always return a |
---|
| 1707 | # "True" value (i.e. a BinaryClause...) |
---|
| 1708 | return col in util.column_set(self) |
---|
| 1709 | |
---|
| 1710 | class ColumnSet(util.ordered_column_set): |
---|
| 1711 | def contains_column(self, col): |
---|
| 1712 | return col in self |
---|
| 1713 | |
---|
| 1714 | def extend(self, cols): |
---|
| 1715 | for col in cols: |
---|
| 1716 | self.add(col) |
---|
| 1717 | |
---|
| 1718 | def __add__(self, other): |
---|
| 1719 | return list(self) + list(other) |
---|
| 1720 | |
---|
| 1721 | def __eq__(self, other): |
---|
| 1722 | l = [] |
---|
| 1723 | for c in other: |
---|
| 1724 | for local in self: |
---|
| 1725 | if c.shares_lineage(local): |
---|
| 1726 | l.append(c==local) |
---|
| 1727 | return and_(*l) |
---|
| 1728 | |
---|
| 1729 | def __hash__(self): |
---|
| 1730 | return hash(tuple(x for x in self)) |
---|
| 1731 | |
---|
| 1732 | class Selectable(ClauseElement): |
---|
| 1733 | """mark a class as being selectable""" |
---|
| 1734 | __visit_name__ = 'selectable' |
---|
| 1735 | |
---|
| 1736 | class FromClause(Selectable): |
---|
| 1737 | """Represent an element that can be used within the ``FROM`` clause of a ``SELECT`` statement.""" |
---|
| 1738 | |
---|
| 1739 | __visit_name__ = 'fromclause' |
---|
| 1740 | named_with_column = False |
---|
| 1741 | _hide_froms = [] |
---|
| 1742 | quote = None |
---|
| 1743 | schema = None |
---|
| 1744 | |
---|
| 1745 | def count(self, whereclause=None, **params): |
---|
| 1746 | """return a SELECT COUNT generated against this ``FromClause``.""" |
---|
| 1747 | |
---|
| 1748 | if self.primary_key: |
---|
| 1749 | col = list(self.primary_key)[0] |
---|
| 1750 | else: |
---|
| 1751 | col = list(self.columns)[0] |
---|
| 1752 | return select([func.count(col).label('tbl_row_count')], whereclause, from_obj=[self], **params) |
---|
| 1753 | |
---|
| 1754 | def select(self, whereclause=None, **params): |
---|
| 1755 | """return a SELECT of this ``FromClause``.""" |
---|
| 1756 | |
---|
| 1757 | return select([self], whereclause, **params) |
---|
| 1758 | |
---|
| 1759 | def join(self, right, onclause=None, isouter=False): |
---|
| 1760 | """return a join of this ``FromClause`` against another ``FromClause``.""" |
---|
| 1761 | |
---|
| 1762 | return Join(self, right, onclause, isouter) |
---|
| 1763 | |
---|
| 1764 | def outerjoin(self, right, onclause=None): |
---|
| 1765 | """return an outer join of this ``FromClause`` against another ``FromClause``.""" |
---|
| 1766 | |
---|
| 1767 | return Join(self, right, onclause, True) |
---|
| 1768 | |
---|
| 1769 | def alias(self, name=None): |
---|
| 1770 | """return an alias of this ``FromClause``. |
---|
| 1771 | |
---|
| 1772 | For table objects, this has the effect of the table being rendered |
---|
| 1773 | as ``tablename AS aliasname`` in a SELECT statement. |
---|
| 1774 | For select objects, the effect is that of creating a named |
---|
| 1775 | subquery, i.e. ``(select ...) AS aliasname``. |
---|
| 1776 | The ``alias()`` method is the general way to create |
---|
| 1777 | a "subquery" out of an existing SELECT. |
---|
| 1778 | |
---|
| 1779 | The ``name`` parameter is optional, and if left blank an |
---|
| 1780 | "anonymous" name will be generated at compile time, guaranteed |
---|
| 1781 | to be unique against other anonymous constructs used in the |
---|
| 1782 | same statement. |
---|
| 1783 | |
---|
| 1784 | """ |
---|
| 1785 | |
---|
| 1786 | return Alias(self, name) |
---|
| 1787 | |
---|
| 1788 | def is_derived_from(self, fromclause): |
---|
| 1789 | """Return True if this FromClause is 'derived' from the given FromClause. |
---|
| 1790 | |
---|
| 1791 | An example would be an Alias of a Table is derived from that Table. |
---|
| 1792 | |
---|
| 1793 | """ |
---|
| 1794 | return fromclause in self._cloned_set |
---|
| 1795 | |
---|
| 1796 | def replace_selectable(self, old, alias): |
---|
| 1797 | """replace all occurences of FromClause 'old' with the given Alias object, returning a copy of this ``FromClause``.""" |
---|
| 1798 | |
---|
| 1799 | global ClauseAdapter |
---|
| 1800 | if ClauseAdapter is None: |
---|
| 1801 | from sqlalchemy.sql.util import ClauseAdapter |
---|
| 1802 | return ClauseAdapter(alias).traverse(self) |
---|
| 1803 | |
---|
| 1804 | def correspond_on_equivalents(self, column, equivalents): |
---|
| 1805 | """Return corresponding_column for the given column, or if None |
---|
| 1806 | search for a match in the given dictionary. |
---|
| 1807 | |
---|
| 1808 | """ |
---|
| 1809 | col = self.corresponding_column(column, require_embedded=True) |
---|
| 1810 | if col is None and col in equivalents: |
---|
| 1811 | for equiv in equivalents[col]: |
---|
| 1812 | nc = self.corresponding_column(equiv, require_embedded=True) |
---|
| 1813 | if nc: |
---|
| 1814 | return nc |
---|
| 1815 | return col |
---|
| 1816 | |
---|
| 1817 | def corresponding_column(self, column, require_embedded=False): |
---|
| 1818 | """Given a ``ColumnElement``, return the exported ``ColumnElement`` |
---|
| 1819 | object from this ``Selectable`` which corresponds to that |
---|
| 1820 | original ``Column`` via a common anscestor column. |
---|
| 1821 | |
---|
| 1822 | :param column: the target ``ColumnElement`` to be matched |
---|
| 1823 | |
---|
| 1824 | :param require_embedded: only return corresponding columns for the given |
---|
| 1825 | ``ColumnElement``, if the given ``ColumnElement`` is |
---|
| 1826 | actually present within a sub-element of this |
---|
| 1827 | ``FromClause``. Normally the column will match if it merely |
---|
| 1828 | shares a common anscestor with one of the exported columns |
---|
| 1829 | of this ``FromClause``. |
---|
| 1830 | |
---|
| 1831 | """ |
---|
| 1832 | # dont dig around if the column is locally present |
---|
| 1833 | if self.c.contains_column(column): |
---|
| 1834 | return column |
---|
| 1835 | |
---|
| 1836 | col, intersect = None, None |
---|
| 1837 | target_set = column.proxy_set |
---|
| 1838 | cols = self.c |
---|
| 1839 | for c in cols: |
---|
| 1840 | i = c.proxy_set.intersection(target_set) |
---|
| 1841 | if i and \ |
---|
| 1842 | (not require_embedded or c.proxy_set.issuperset(target_set)): |
---|
| 1843 | |
---|
| 1844 | if col is None: |
---|
| 1845 | # no corresponding column yet, pick this one. |
---|
| 1846 | col, intersect = c, i |
---|
| 1847 | elif len(i) > len(intersect): |
---|
| 1848 | # 'c' has a larger field of correspondence than 'col'. |
---|
| 1849 | # i.e. selectable.c.a1_x->a1.c.x->table.c.x matches a1.c.x->table.c.x better than |
---|
| 1850 | # selectable.c.x->table.c.x does. |
---|
| 1851 | col, intersect = c, i |
---|
| 1852 | elif i == intersect: |
---|
| 1853 | # they have the same field of correspondence. |
---|
| 1854 | # see which proxy_set has fewer columns in it, which indicates a |
---|
| 1855 | # closer relationship with the root column. Also take into account the |
---|
| 1856 | # "weight" attribute which CompoundSelect() uses to give higher precedence to |
---|
| 1857 | # columns based on vertical position in the compound statement, and discard columns |
---|
| 1858 | # that have no reference to the target column (also occurs with CompoundSelect) |
---|
| 1859 | col_distance = util.reduce(operator.add, |
---|
| 1860 | [sc._annotations.get('weight', 1) for sc in col.proxy_set if sc.shares_lineage(column)] |
---|
| 1861 | ) |
---|
| 1862 | c_distance = util.reduce(operator.add, |
---|
| 1863 | [sc._annotations.get('weight', 1) for sc in c.proxy_set if sc.shares_lineage(column)] |
---|
| 1864 | ) |
---|
| 1865 | if \ |
---|
| 1866 | c_distance < col_distance: |
---|
| 1867 | col, intersect = c, i |
---|
| 1868 | return col |
---|
| 1869 | |
---|
| 1870 | @property |
---|
| 1871 | def description(self): |
---|
| 1872 | """a brief description of this FromClause. |
---|
| 1873 | |
---|
| 1874 | Used primarily for error message formatting. |
---|
| 1875 | |
---|
| 1876 | """ |
---|
| 1877 | return getattr(self, 'name', self.__class__.__name__ + " object") |
---|
| 1878 | |
---|
| 1879 | def _reset_exported(self): |
---|
| 1880 | """delete memoized collections when a FromClause is cloned.""" |
---|
| 1881 | |
---|
| 1882 | for attr in ('_columns', '_primary_key' '_foreign_keys', 'locate_all_froms'): |
---|
| 1883 | self.__dict__.pop(attr, None) |
---|
| 1884 | |
---|
| 1885 | @util.memoized_property |
---|
| 1886 | def _columns(self): |
---|
| 1887 | """Return the collection of Column objects contained by this FromClause.""" |
---|
| 1888 | |
---|
| 1889 | self._export_columns() |
---|
| 1890 | return self._columns |
---|
| 1891 | |
---|
| 1892 | @util.memoized_property |
---|
| 1893 | def _primary_key(self): |
---|
| 1894 | """Return the collection of Column objects which comprise the primary key of this FromClause.""" |
---|
| 1895 | |
---|
| 1896 | self._export_columns() |
---|
| 1897 | return self._primary_key |
---|
| 1898 | |
---|
| 1899 | @util.memoized_property |
---|
| 1900 | def _foreign_keys(self): |
---|
| 1901 | """Return the collection of ForeignKey objects which this FromClause references.""" |
---|
| 1902 | |
---|
| 1903 | self._export_columns() |
---|
| 1904 | return self._foreign_keys |
---|
| 1905 | |
---|
| 1906 | columns = property(attrgetter('_columns'), doc=_columns.__doc__) |
---|
| 1907 | primary_key = property(attrgetter('_primary_key'), doc=_primary_key.__doc__) |
---|
| 1908 | foreign_keys = property(attrgetter('_foreign_keys'), doc=_foreign_keys.__doc__) |
---|
| 1909 | |
---|
| 1910 | # synonyms for 'columns' |
---|
| 1911 | c = _select_iterable = property(attrgetter('columns'), doc=_columns.__doc__) |
---|
| 1912 | |
---|
| 1913 | def _export_columns(self): |
---|
| 1914 | """Initialize column collections.""" |
---|
| 1915 | |
---|
| 1916 | self._columns = ColumnCollection() |
---|
| 1917 | self._primary_key = ColumnSet() |
---|
| 1918 | self._foreign_keys = set() |
---|
| 1919 | self._populate_column_collection() |
---|
| 1920 | |
---|
| 1921 | def _populate_column_collection(self): |
---|
| 1922 | pass |
---|
| 1923 | |
---|
| 1924 | class _BindParamClause(ColumnElement): |
---|
| 1925 | """Represent a bind parameter. |
---|
| 1926 | |
---|
| 1927 | Public constructor is the ``bindparam()`` function. |
---|
| 1928 | |
---|
| 1929 | """ |
---|
| 1930 | |
---|
| 1931 | __visit_name__ = 'bindparam' |
---|
| 1932 | quote = None |
---|
| 1933 | |
---|
| 1934 | def __init__(self, key, value, type_=None, unique=False, isoutparam=False, shortname=None): |
---|
| 1935 | """Construct a _BindParamClause. |
---|
| 1936 | |
---|
| 1937 | key |
---|
| 1938 | the key for this bind param. Will be used in the generated |
---|
| 1939 | SQL statement for dialects that use named parameters. This |
---|
| 1940 | value may be modified when part of a compilation operation, |
---|
| 1941 | if other ``_BindParamClause`` objects exist with the same |
---|
| 1942 | key, or if its length is too long and truncation is |
---|
| 1943 | required. |
---|
| 1944 | |
---|
| 1945 | value |
---|
| 1946 | Initial value for this bind param. This value may be |
---|
| 1947 | overridden by the dictionary of parameters sent to statement |
---|
| 1948 | compilation/execution. |
---|
| 1949 | |
---|
| 1950 | shortname |
---|
| 1951 | deprecated. |
---|
| 1952 | |
---|
| 1953 | type\_ |
---|
| 1954 | A ``TypeEngine`` object that will be used to pre-process the |
---|
| 1955 | value corresponding to this ``_BindParamClause`` at |
---|
| 1956 | execution time. |
---|
| 1957 | |
---|
| 1958 | unique |
---|
| 1959 | if True, the key name of this BindParamClause will be |
---|
| 1960 | modified if another ``_BindParamClause`` of the same name |
---|
| 1961 | already has been located within the containing |
---|
| 1962 | ``ClauseElement``. |
---|
| 1963 | |
---|
| 1964 | isoutparam |
---|
| 1965 | if True, the parameter should be treated like a stored procedure "OUT" |
---|
| 1966 | parameter. |
---|
| 1967 | |
---|
| 1968 | """ |
---|
| 1969 | if unique: |
---|
| 1970 | self.key = _generated_label("%%(%d %s)s" % (id(self), key or 'param')) |
---|
| 1971 | else: |
---|
| 1972 | self.key = key or _generated_label("%%(%d param)s" % id(self)) |
---|
| 1973 | self._orig_key = key or 'param' |
---|
| 1974 | self.unique = unique |
---|
| 1975 | self.value = value |
---|
| 1976 | self.isoutparam = isoutparam |
---|
| 1977 | self.shortname = shortname |
---|
| 1978 | |
---|
| 1979 | if type_ is None: |
---|
| 1980 | self.type = sqltypes.type_map.get(type(value), sqltypes.NullType)() |
---|
| 1981 | elif isinstance(type_, type): |
---|
| 1982 | self.type = type_() |
---|
| 1983 | else: |
---|
| 1984 | self.type = type_ |
---|
| 1985 | |
---|
| 1986 | def _clone(self): |
---|
| 1987 | c = ClauseElement._clone(self) |
---|
| 1988 | if self.unique: |
---|
| 1989 | c.key = _generated_label("%%(%d %s)s" % (id(c), c._orig_key or 'param')) |
---|
| 1990 | return c |
---|
| 1991 | |
---|
| 1992 | def _convert_to_unique(self): |
---|
| 1993 | if not self.unique: |
---|
| 1994 | self.unique = True |
---|
| 1995 | self.key = _generated_label("%%(%d %s)s" % (id(self), self._orig_key or 'param')) |
---|
| 1996 | |
---|
| 1997 | def bind_processor(self, dialect): |
---|
| 1998 | return self.type.dialect_impl(dialect).bind_processor(dialect) |
---|
| 1999 | |
---|
| 2000 | def _compare_type(self, obj): |
---|
| 2001 | if not isinstance(self.type, sqltypes.NullType): |
---|
| 2002 | return self.type |
---|
| 2003 | else: |
---|
| 2004 | return obj.type |
---|
| 2005 | |
---|
| 2006 | def compare(self, other): |
---|
| 2007 | """Compare this ``_BindParamClause`` to the given clause. |
---|
| 2008 | |
---|
| 2009 | Since ``compare()`` is meant to compare statement syntax, this |
---|
| 2010 | method returns True if the two ``_BindParamClauses`` have just |
---|
| 2011 | the same type. |
---|
| 2012 | |
---|
| 2013 | """ |
---|
| 2014 | return isinstance(other, _BindParamClause) and other.type.__class__ == self.type.__class__ and self.value == other.value |
---|
| 2015 | |
---|
| 2016 | def __getstate__(self): |
---|
| 2017 | """execute a deferred value for serialization purposes.""" |
---|
| 2018 | |
---|
| 2019 | d = self.__dict__.copy() |
---|
| 2020 | v = self.value |
---|
| 2021 | if util.callable(v): |
---|
| 2022 | v = v() |
---|
| 2023 | d['value'] = v |
---|
| 2024 | return d |
---|
| 2025 | |
---|
| 2026 | def __repr__(self): |
---|
| 2027 | return "_BindParamClause(%s, %s, type_=%s)" % (repr(self.key), repr(self.value), repr(self.type)) |
---|
| 2028 | |
---|
| 2029 | class _TypeClause(ClauseElement): |
---|
| 2030 | """Handle a type keyword in a SQL statement. |
---|
| 2031 | |
---|
| 2032 | Used by the ``Case`` statement. |
---|
| 2033 | |
---|
| 2034 | """ |
---|
| 2035 | |
---|
| 2036 | __visit_name__ = 'typeclause' |
---|
| 2037 | |
---|
| 2038 | def __init__(self, type): |
---|
| 2039 | self.type = type |
---|
| 2040 | |
---|
| 2041 | |
---|
| 2042 | class _TextClause(ClauseElement): |
---|
| 2043 | """Represent a literal SQL text fragment. |
---|
| 2044 | |
---|
| 2045 | Public constructor is the ``text()`` function. |
---|
| 2046 | |
---|
| 2047 | """ |
---|
| 2048 | |
---|
| 2049 | __visit_name__ = 'textclause' |
---|
| 2050 | |
---|
| 2051 | _bind_params_regex = re.compile(r'(?<![:\w\x5c]):(\w+)(?!:)', re.UNICODE) |
---|
| 2052 | supports_execution = True |
---|
| 2053 | |
---|
| 2054 | @property |
---|
| 2055 | def _select_iterable(self): |
---|
| 2056 | return (self,) |
---|
| 2057 | |
---|
| 2058 | _hide_froms = [] |
---|
| 2059 | |
---|
| 2060 | def __init__(self, text = "", bind=None, bindparams=None, typemap=None, autocommit=False): |
---|
| 2061 | self._bind = bind |
---|
| 2062 | self.bindparams = {} |
---|
| 2063 | self.typemap = typemap |
---|
| 2064 | self._autocommit = autocommit |
---|
| 2065 | if typemap is not None: |
---|
| 2066 | for key in typemap.keys(): |
---|
| 2067 | typemap[key] = sqltypes.to_instance(typemap[key]) |
---|
| 2068 | |
---|
| 2069 | def repl(m): |
---|
| 2070 | self.bindparams[m.group(1)] = bindparam(m.group(1)) |
---|
| 2071 | return ":%s" % m.group(1) |
---|
| 2072 | |
---|
| 2073 | # scan the string and search for bind parameter names, add them |
---|
| 2074 | # to the list of bindparams |
---|
| 2075 | self.text = self._bind_params_regex.sub(repl, text) |
---|
| 2076 | if bindparams is not None: |
---|
| 2077 | for b in bindparams: |
---|
| 2078 | self.bindparams[b.key] = b |
---|
| 2079 | |
---|
| 2080 | @property |
---|
| 2081 | def type(self): |
---|
| 2082 | if self.typemap is not None and len(self.typemap) == 1: |
---|
| 2083 | return list(self.typemap)[0] |
---|
| 2084 | else: |
---|
| 2085 | return None |
---|
| 2086 | |
---|
| 2087 | def _copy_internals(self, clone=_clone): |
---|
| 2088 | self.bindparams = dict((b.key, clone(b)) |
---|
| 2089 | for b in self.bindparams.values()) |
---|
| 2090 | |
---|
| 2091 | def get_children(self, **kwargs): |
---|
| 2092 | return self.bindparams.values() |
---|
| 2093 | |
---|
| 2094 | |
---|
| 2095 | class _Null(ColumnElement): |
---|
| 2096 | """Represent the NULL keyword in a SQL statement. |
---|
| 2097 | |
---|
| 2098 | Public constructor is the ``null()`` function. |
---|
| 2099 | |
---|
| 2100 | """ |
---|
| 2101 | |
---|
| 2102 | __visit_name__ = 'null' |
---|
| 2103 | |
---|
| 2104 | def __init__(self): |
---|
| 2105 | self.type = sqltypes.NULLTYPE |
---|
| 2106 | |
---|
| 2107 | |
---|
| 2108 | class ClauseList(ClauseElement): |
---|
| 2109 | """Describe a list of clauses, separated by an operator. |
---|
| 2110 | |
---|
| 2111 | By default, is comma-separated, such as a column listing. |
---|
| 2112 | |
---|
| 2113 | """ |
---|
| 2114 | __visit_name__ = 'clauselist' |
---|
| 2115 | |
---|
| 2116 | def __init__(self, *clauses, **kwargs): |
---|
| 2117 | self.operator = kwargs.pop('operator', operators.comma_op) |
---|
| 2118 | self.group = kwargs.pop('group', True) |
---|
| 2119 | self.group_contents = kwargs.pop('group_contents', True) |
---|
| 2120 | if self.group_contents: |
---|
| 2121 | self.clauses = [ |
---|
| 2122 | _literal_as_text(clause).self_group(against=self.operator) |
---|
| 2123 | for clause in clauses if clause is not None] |
---|
| 2124 | else: |
---|
| 2125 | self.clauses = [ |
---|
| 2126 | _literal_as_text(clause) |
---|
| 2127 | for clause in clauses if clause is not None] |
---|
| 2128 | |
---|
| 2129 | def __iter__(self): |
---|
| 2130 | return iter(self.clauses) |
---|
| 2131 | |
---|
| 2132 | def __len__(self): |
---|
| 2133 | return len(self.clauses) |
---|
| 2134 | |
---|
| 2135 | @property |
---|
| 2136 | def _select_iterable(self): |
---|
| 2137 | return iter(self) |
---|
| 2138 | |
---|
| 2139 | def append(self, clause): |
---|
| 2140 | # TODO: not sure if i like the 'group_contents' flag. need to |
---|
| 2141 | # define the difference between a ClauseList of ClauseLists, |
---|
| 2142 | # and a "flattened" ClauseList of ClauseLists. flatten() |
---|
| 2143 | # method ? |
---|
| 2144 | if self.group_contents: |
---|
| 2145 | self.clauses.append(_literal_as_text(clause).self_group(against=self.operator)) |
---|
| 2146 | else: |
---|
| 2147 | self.clauses.append(_literal_as_text(clause)) |
---|
| 2148 | |
---|
| 2149 | def _copy_internals(self, clone=_clone): |
---|
| 2150 | self.clauses = [clone(clause) for clause in self.clauses] |
---|
| 2151 | |
---|
| 2152 | def get_children(self, **kwargs): |
---|
| 2153 | return self.clauses |
---|
| 2154 | |
---|
| 2155 | @property |
---|
| 2156 | def _from_objects(self): |
---|
| 2157 | return list(itertools.chain(*[c._from_objects for c in self.clauses])) |
---|
| 2158 | |
---|
| 2159 | def self_group(self, against=None): |
---|
| 2160 | if self.group and self.operator is not against and operators.is_precedent(self.operator, against): |
---|
| 2161 | return _Grouping(self) |
---|
| 2162 | else: |
---|
| 2163 | return self |
---|
| 2164 | |
---|
| 2165 | def compare(self, other): |
---|
| 2166 | """Compare this ``ClauseList`` to the given ``ClauseList``, |
---|
| 2167 | including a comparison of all the clause items. |
---|
| 2168 | |
---|
| 2169 | """ |
---|
| 2170 | if not isinstance(other, ClauseList) and len(self.clauses) == 1: |
---|
| 2171 | return self.clauses[0].compare(other) |
---|
| 2172 | elif isinstance(other, ClauseList) and len(self.clauses) == len(other.clauses): |
---|
| 2173 | for i in range(0, len(self.clauses)): |
---|
| 2174 | if not self.clauses[i].compare(other.clauses[i]): |
---|
| 2175 | return False |
---|
| 2176 | else: |
---|
| 2177 | return self.operator == other.operator |
---|
| 2178 | else: |
---|
| 2179 | return False |
---|
| 2180 | |
---|
| 2181 | class BooleanClauseList(ClauseList, ColumnElement): |
---|
| 2182 | __visit_name__ = 'clauselist' |
---|
| 2183 | |
---|
| 2184 | def __init__(self, *clauses, **kwargs): |
---|
| 2185 | super(BooleanClauseList, self).__init__(*clauses, **kwargs) |
---|
| 2186 | self.type = sqltypes.to_instance(kwargs.get('type_', sqltypes.Boolean)) |
---|
| 2187 | |
---|
| 2188 | @property |
---|
| 2189 | def _select_iterable(self): |
---|
| 2190 | return (self, ) |
---|
| 2191 | |
---|
| 2192 | |
---|
| 2193 | class _Case(ColumnElement): |
---|
| 2194 | __visit_name__ = 'case' |
---|
| 2195 | |
---|
| 2196 | def __init__(self, whens, value=None, else_=None): |
---|
| 2197 | try: |
---|
| 2198 | whens = util.dictlike_iteritems(whens) |
---|
| 2199 | except TypeError: |
---|
| 2200 | pass |
---|
| 2201 | |
---|
| 2202 | if value: |
---|
| 2203 | whenlist = [(_literal_as_binds(c).self_group(), _literal_as_binds(r)) for (c, r) in whens] |
---|
| 2204 | else: |
---|
| 2205 | whenlist = [(_no_literals(c).self_group(), _literal_as_binds(r)) for (c, r) in whens] |
---|
| 2206 | |
---|
| 2207 | if whenlist: |
---|
| 2208 | type_ = list(whenlist[-1])[-1].type |
---|
| 2209 | else: |
---|
| 2210 | type_ = None |
---|
| 2211 | |
---|
| 2212 | if value is None: |
---|
| 2213 | self.value = None |
---|
| 2214 | else: |
---|
| 2215 | self.value = _literal_as_binds(value) |
---|
| 2216 | |
---|
| 2217 | self.type = type_ |
---|
| 2218 | self.whens = whenlist |
---|
| 2219 | if else_ is not None: |
---|
| 2220 | self.else_ = _literal_as_binds(else_) |
---|
| 2221 | else: |
---|
| 2222 | self.else_ = None |
---|
| 2223 | |
---|
| 2224 | def _copy_internals(self, clone=_clone): |
---|
| 2225 | if self.value: |
---|
| 2226 | self.value = clone(self.value) |
---|
| 2227 | self.whens = [(clone(x), clone(y)) for x, y in self.whens] |
---|
| 2228 | if self.else_: |
---|
| 2229 | self.else_ = clone(self.else_) |
---|
| 2230 | |
---|
| 2231 | def get_children(self, **kwargs): |
---|
| 2232 | if self.value: |
---|
| 2233 | yield self.value |
---|
| 2234 | for x, y in self.whens: |
---|
| 2235 | yield x |
---|
| 2236 | yield y |
---|
| 2237 | if self.else_: |
---|
| 2238 | yield self.else_ |
---|
| 2239 | |
---|
| 2240 | @property |
---|
| 2241 | def _from_objects(self): |
---|
| 2242 | return list(itertools.chain(*[x._from_objects for x in self.get_children()])) |
---|
| 2243 | |
---|
| 2244 | class Function(ColumnElement, FromClause): |
---|
| 2245 | """Describe a SQL function.""" |
---|
| 2246 | |
---|
| 2247 | __visit_name__ = 'function' |
---|
| 2248 | |
---|
| 2249 | def __init__(self, name, *clauses, **kwargs): |
---|
| 2250 | self.packagenames = kwargs.get('packagenames', None) or [] |
---|
| 2251 | self.name = name |
---|
| 2252 | self._bind = kwargs.get('bind', None) |
---|
| 2253 | args = [_literal_as_binds(c, self.name) for c in clauses] |
---|
| 2254 | self.clause_expr = ClauseList(operator=operators.comma_op, group_contents=True, *args).self_group() |
---|
| 2255 | self.type = sqltypes.to_instance(kwargs.get('type_', None)) |
---|
| 2256 | |
---|
| 2257 | @property |
---|
| 2258 | def key(self): |
---|
| 2259 | return self.name |
---|
| 2260 | |
---|
| 2261 | @property |
---|
| 2262 | def columns(self): |
---|
| 2263 | return [self] |
---|
| 2264 | |
---|
| 2265 | @util.memoized_property |
---|
| 2266 | def clauses(self): |
---|
| 2267 | return self.clause_expr.element |
---|
| 2268 | |
---|
| 2269 | @property |
---|
| 2270 | def _from_objects(self): |
---|
| 2271 | return self.clauses._from_objects |
---|
| 2272 | |
---|
| 2273 | def get_children(self, **kwargs): |
---|
| 2274 | return self.clause_expr, |
---|
| 2275 | |
---|
| 2276 | def _copy_internals(self, clone=_clone): |
---|
| 2277 | self.clause_expr = clone(self.clause_expr) |
---|
| 2278 | self._reset_exported() |
---|
| 2279 | util.reset_memoized(self, 'clauses') |
---|
| 2280 | |
---|
| 2281 | def _bind_param(self, obj): |
---|
| 2282 | return _BindParamClause(self.name, obj, type_=self.type, unique=True) |
---|
| 2283 | |
---|
| 2284 | def select(self): |
---|
| 2285 | return select([self]) |
---|
| 2286 | |
---|
| 2287 | def scalar(self): |
---|
| 2288 | return select([self]).execute().scalar() |
---|
| 2289 | |
---|
| 2290 | def execute(self): |
---|
| 2291 | return select([self]).execute() |
---|
| 2292 | |
---|
| 2293 | def _compare_type(self, obj): |
---|
| 2294 | return self.type |
---|
| 2295 | |
---|
| 2296 | |
---|
| 2297 | class _Cast(ColumnElement): |
---|
| 2298 | |
---|
| 2299 | __visit_name__ = 'cast' |
---|
| 2300 | |
---|
| 2301 | def __init__(self, clause, totype, **kwargs): |
---|
| 2302 | self.type = sqltypes.to_instance(totype) |
---|
| 2303 | self.clause = _literal_as_binds(clause, None) |
---|
| 2304 | self.typeclause = _TypeClause(self.type) |
---|
| 2305 | |
---|
| 2306 | def _copy_internals(self, clone=_clone): |
---|
| 2307 | self.clause = clone(self.clause) |
---|
| 2308 | self.typeclause = clone(self.typeclause) |
---|
| 2309 | |
---|
| 2310 | def get_children(self, **kwargs): |
---|
| 2311 | return self.clause, self.typeclause |
---|
| 2312 | |
---|
| 2313 | @property |
---|
| 2314 | def _from_objects(self): |
---|
| 2315 | return self.clause._from_objects |
---|
| 2316 | |
---|
| 2317 | |
---|
| 2318 | class _Extract(ColumnElement): |
---|
| 2319 | |
---|
| 2320 | __visit_name__ = 'extract' |
---|
| 2321 | |
---|
| 2322 | def __init__(self, field, expr, **kwargs): |
---|
| 2323 | self.type = sqltypes.Integer() |
---|
| 2324 | self.field = field |
---|
| 2325 | self.expr = _literal_as_binds(expr, None) |
---|
| 2326 | |
---|
| 2327 | def _copy_internals(self, clone=_clone): |
---|
| 2328 | self.expr = clone(self.expr) |
---|
| 2329 | |
---|
| 2330 | def get_children(self, **kwargs): |
---|
| 2331 | return self.expr, |
---|
| 2332 | |
---|
| 2333 | @property |
---|
| 2334 | def _from_objects(self): |
---|
| 2335 | return self.expr._from_objects |
---|
| 2336 | |
---|
| 2337 | |
---|
| 2338 | class _UnaryExpression(ColumnElement): |
---|
| 2339 | |
---|
| 2340 | __visit_name__ = 'unary' |
---|
| 2341 | |
---|
| 2342 | def __init__(self, element, operator=None, modifier=None, type_=None, negate=None): |
---|
| 2343 | self.operator = operator |
---|
| 2344 | self.modifier = modifier |
---|
| 2345 | |
---|
| 2346 | self.element = _literal_as_text(element).self_group(against=self.operator or self.modifier) |
---|
| 2347 | self.type = sqltypes.to_instance(type_) |
---|
| 2348 | self.negate = negate |
---|
| 2349 | |
---|
| 2350 | @property |
---|
| 2351 | def _from_objects(self): |
---|
| 2352 | return self.element._from_objects |
---|
| 2353 | |
---|
| 2354 | def _copy_internals(self, clone=_clone): |
---|
| 2355 | self.element = clone(self.element) |
---|
| 2356 | |
---|
| 2357 | def get_children(self, **kwargs): |
---|
| 2358 | return self.element, |
---|
| 2359 | |
---|
| 2360 | def compare(self, other): |
---|
| 2361 | """Compare this ``_UnaryExpression`` against the given ``ClauseElement``.""" |
---|
| 2362 | |
---|
| 2363 | return ( |
---|
| 2364 | isinstance(other, _UnaryExpression) and |
---|
| 2365 | self.operator == other.operator and |
---|
| 2366 | self.modifier == other.modifier and |
---|
| 2367 | self.element.compare(other.element) |
---|
| 2368 | ) |
---|
| 2369 | |
---|
| 2370 | def _negate(self): |
---|
| 2371 | if self.negate is not None: |
---|
| 2372 | return _UnaryExpression( |
---|
| 2373 | self.element, |
---|
| 2374 | operator=self.negate, |
---|
| 2375 | negate=self.operator, |
---|
| 2376 | modifier=self.modifier, |
---|
| 2377 | type_=self.type) |
---|
| 2378 | else: |
---|
| 2379 | return super(_UnaryExpression, self)._negate() |
---|
| 2380 | |
---|
| 2381 | def self_group(self, against): |
---|
| 2382 | if self.operator and operators.is_precedent(self.operator, against): |
---|
| 2383 | return _Grouping(self) |
---|
| 2384 | else: |
---|
| 2385 | return self |
---|
| 2386 | |
---|
| 2387 | |
---|
| 2388 | class _BinaryExpression(ColumnElement): |
---|
| 2389 | """Represent an expression that is ``LEFT <operator> RIGHT``.""" |
---|
| 2390 | |
---|
| 2391 | __visit_name__ = 'binary' |
---|
| 2392 | |
---|
| 2393 | def __init__(self, left, right, operator, type_=None, negate=None, modifiers=None): |
---|
| 2394 | self.left = _literal_as_text(left).self_group(against=operator) |
---|
| 2395 | self.right = _literal_as_text(right).self_group(against=operator) |
---|
| 2396 | self.operator = operator |
---|
| 2397 | self.type = sqltypes.to_instance(type_) |
---|
| 2398 | self.negate = negate |
---|
| 2399 | if modifiers is None: |
---|
| 2400 | self.modifiers = {} |
---|
| 2401 | else: |
---|
| 2402 | self.modifiers = modifiers |
---|
| 2403 | |
---|
| 2404 | @property |
---|
| 2405 | def _from_objects(self): |
---|
| 2406 | return self.left._from_objects + self.right._from_objects |
---|
| 2407 | |
---|
| 2408 | def _copy_internals(self, clone=_clone): |
---|
| 2409 | self.left = clone(self.left) |
---|
| 2410 | self.right = clone(self.right) |
---|
| 2411 | |
---|
| 2412 | def get_children(self, **kwargs): |
---|
| 2413 | return self.left, self.right |
---|
| 2414 | |
---|
| 2415 | def compare(self, other): |
---|
| 2416 | """Compare this ``_BinaryExpression`` against the given ``_BinaryExpression``.""" |
---|
| 2417 | |
---|
| 2418 | return ( |
---|
| 2419 | isinstance(other, _BinaryExpression) and |
---|
| 2420 | self.operator == other.operator and |
---|
| 2421 | ( |
---|
| 2422 | self.left.compare(other.left) and |
---|
| 2423 | self.right.compare(other.right) or |
---|
| 2424 | ( |
---|
| 2425 | operators.is_commutative(self.operator) and |
---|
| 2426 | self.left.compare(other.right) and |
---|
| 2427 | self.right.compare(other.left) |
---|
| 2428 | ) |
---|
| 2429 | ) |
---|
| 2430 | ) |
---|
| 2431 | |
---|
| 2432 | def self_group(self, against=None): |
---|
| 2433 | # use small/large defaults for comparison so that unknown |
---|
| 2434 | # operators are always parenthesized |
---|
| 2435 | if self.operator is not against and operators.is_precedent(self.operator, against): |
---|
| 2436 | return _Grouping(self) |
---|
| 2437 | else: |
---|
| 2438 | return self |
---|
| 2439 | |
---|
| 2440 | def _negate(self): |
---|
| 2441 | if self.negate is not None: |
---|
| 2442 | return _BinaryExpression( |
---|
| 2443 | self.left, |
---|
| 2444 | self.right, |
---|
| 2445 | self.negate, |
---|
| 2446 | negate=self.operator, |
---|
| 2447 | type_=self.type, |
---|
| 2448 | modifiers=self.modifiers) |
---|
| 2449 | else: |
---|
| 2450 | return super(_BinaryExpression, self)._negate() |
---|
| 2451 | |
---|
| 2452 | class _Exists(_UnaryExpression): |
---|
| 2453 | __visit_name__ = _UnaryExpression.__visit_name__ |
---|
| 2454 | _from_objects = [] |
---|
| 2455 | |
---|
| 2456 | def __init__(self, *args, **kwargs): |
---|
| 2457 | if args and isinstance(args[0], _SelectBaseMixin): |
---|
| 2458 | s = args[0] |
---|
| 2459 | else: |
---|
| 2460 | if not args: |
---|
| 2461 | args = ([literal_column('*')],) |
---|
| 2462 | s = select(*args, **kwargs).as_scalar().self_group() |
---|
| 2463 | |
---|
| 2464 | _UnaryExpression.__init__(self, s, operator=operators.exists, type_=sqltypes.Boolean) |
---|
| 2465 | |
---|
| 2466 | def select(self, whereclause=None, **params): |
---|
| 2467 | return select([self], whereclause, **params) |
---|
| 2468 | |
---|
| 2469 | def correlate(self, fromclause): |
---|
| 2470 | e = self._clone() |
---|
| 2471 | e.element = self.element.correlate(fromclause).self_group() |
---|
| 2472 | return e |
---|
| 2473 | |
---|
| 2474 | def select_from(self, clause): |
---|
| 2475 | """return a new exists() construct with the given expression set as its FROM clause.""" |
---|
| 2476 | |
---|
| 2477 | e = self._clone() |
---|
| 2478 | e.element = self.element.select_from(clause).self_group() |
---|
| 2479 | return e |
---|
| 2480 | |
---|
| 2481 | def where(self, clause): |
---|
| 2482 | """return a new exists() construct with the given expression added to its WHERE clause, joined |
---|
| 2483 | to the existing clause via AND, if any.""" |
---|
| 2484 | |
---|
| 2485 | e = self._clone() |
---|
| 2486 | e.element = self.element.where(clause).self_group() |
---|
| 2487 | return e |
---|
| 2488 | |
---|
| 2489 | class Join(FromClause): |
---|
| 2490 | """represent a ``JOIN`` construct between two ``FromClause`` elements. |
---|
| 2491 | |
---|
| 2492 | The public constructor function for ``Join`` is the module-level |
---|
| 2493 | ``join()`` function, as well as the ``join()`` method available |
---|
| 2494 | off all ``FromClause`` subclasses. |
---|
| 2495 | |
---|
| 2496 | """ |
---|
| 2497 | __visit_name__ = 'join' |
---|
| 2498 | |
---|
| 2499 | def __init__(self, left, right, onclause=None, isouter=False): |
---|
| 2500 | self.left = _literal_as_text(left) |
---|
| 2501 | self.right = _literal_as_text(right).self_group() |
---|
| 2502 | |
---|
| 2503 | if onclause is None: |
---|
| 2504 | self.onclause = self._match_primaries(self.left, self.right) |
---|
| 2505 | else: |
---|
| 2506 | self.onclause = onclause |
---|
| 2507 | |
---|
| 2508 | self.isouter = isouter |
---|
| 2509 | self.__folded_equivalents = None |
---|
| 2510 | |
---|
| 2511 | @property |
---|
| 2512 | def description(self): |
---|
| 2513 | return "Join object on %s(%d) and %s(%d)" % ( |
---|
| 2514 | self.left.description, |
---|
| 2515 | id(self.left), |
---|
| 2516 | self.right.description, |
---|
| 2517 | id(self.right)) |
---|
| 2518 | |
---|
| 2519 | def is_derived_from(self, fromclause): |
---|
| 2520 | return fromclause is self or self.left.is_derived_from(fromclause) or self.right.is_derived_from(fromclause) |
---|
| 2521 | |
---|
| 2522 | def self_group(self, against=None): |
---|
| 2523 | return _FromGrouping(self) |
---|
| 2524 | |
---|
| 2525 | def _populate_column_collection(self): |
---|
| 2526 | columns = [c for c in self.left.columns] + [c for c in self.right.columns] |
---|
| 2527 | |
---|
| 2528 | global sql_util |
---|
| 2529 | if not sql_util: |
---|
| 2530 | from sqlalchemy.sql import util as sql_util |
---|
| 2531 | self._primary_key.extend(sql_util.reduce_columns( |
---|
| 2532 | (c for c in columns if c.primary_key), self.onclause)) |
---|
| 2533 | self._columns.update((col._label, col) for col in columns) |
---|
| 2534 | self._foreign_keys.update(itertools.chain(*[col.foreign_keys for col in columns])) |
---|
| 2535 | |
---|
| 2536 | def _copy_internals(self, clone=_clone): |
---|
| 2537 | self._reset_exported() |
---|
| 2538 | self.left = clone(self.left) |
---|
| 2539 | self.right = clone(self.right) |
---|
| 2540 | self.onclause = clone(self.onclause) |
---|
| 2541 | self.__folded_equivalents = None |
---|
| 2542 | |
---|
| 2543 | def get_children(self, **kwargs): |
---|
| 2544 | return self.left, self.right, self.onclause |
---|
| 2545 | |
---|
| 2546 | def _match_primaries(self, primary, secondary): |
---|
| 2547 | global sql_util |
---|
| 2548 | if not sql_util: |
---|
| 2549 | from sqlalchemy.sql import util as sql_util |
---|
| 2550 | return sql_util.join_condition(primary, secondary) |
---|
| 2551 | |
---|
| 2552 | def select(self, whereclause=None, fold_equivalents=False, **kwargs): |
---|
| 2553 | """Create a :class:`Select` from this :class:`Join`. |
---|
| 2554 | |
---|
| 2555 | :param whereclause: the WHERE criterion that will be sent to |
---|
| 2556 | the :func:`select()` function |
---|
| 2557 | |
---|
| 2558 | :param fold_equivalents: based on the join criterion of this |
---|
| 2559 | :class:`Join`, do not include |
---|
| 2560 | repeat column names in the column list of the resulting |
---|
| 2561 | select, for columns that are calculated to be "equivalent" |
---|
| 2562 | based on the join criterion of this :class:`Join`. This will |
---|
| 2563 | recursively apply to any joins directly nested by this one |
---|
| 2564 | as well. This flag is specific to a particular use case |
---|
| 2565 | by the ORM and will be deprecated in 0.6. |
---|
| 2566 | |
---|
| 2567 | :param \**kwargs: all other kwargs are sent to the |
---|
| 2568 | underlying :func:`select()` function. |
---|
| 2569 | |
---|
| 2570 | """ |
---|
| 2571 | if fold_equivalents: |
---|
| 2572 | global sql_util |
---|
| 2573 | if not sql_util: |
---|
| 2574 | from sqlalchemy.sql import util as sql_util |
---|
| 2575 | collist = sql_util.folded_equivalents(self) |
---|
| 2576 | else: |
---|
| 2577 | collist = [self.left, self.right] |
---|
| 2578 | |
---|
| 2579 | return select(collist, whereclause, from_obj=[self], **kwargs) |
---|
| 2580 | |
---|
| 2581 | @property |
---|
| 2582 | def bind(self): |
---|
| 2583 | return self.left.bind or self.right.bind |
---|
| 2584 | |
---|
| 2585 | def alias(self, name=None): |
---|
| 2586 | """Create a ``Select`` out of this ``Join`` clause and return an ``Alias`` of it. |
---|
| 2587 | |
---|
| 2588 | The ``Select`` is not correlating. |
---|
| 2589 | |
---|
| 2590 | """ |
---|
| 2591 | return self.select(use_labels=True, correlate=False).alias(name) |
---|
| 2592 | |
---|
| 2593 | @property |
---|
| 2594 | def _hide_froms(self): |
---|
| 2595 | return itertools.chain(*[_from_objects(x.left, x.right) for x in self._cloned_set]) |
---|
| 2596 | |
---|
| 2597 | @property |
---|
| 2598 | def _from_objects(self): |
---|
| 2599 | return [self] + \ |
---|
| 2600 | self.onclause._from_objects + \ |
---|
| 2601 | self.left._from_objects + \ |
---|
| 2602 | self.right._from_objects |
---|
| 2603 | |
---|
| 2604 | class Alias(FromClause): |
---|
| 2605 | """Represents an table or selectable alias (AS). |
---|
| 2606 | |
---|
| 2607 | Represents an alias, as typically applied to any table or |
---|
| 2608 | sub-select within a SQL statement using the ``AS`` keyword (or |
---|
| 2609 | without the keyword on certain databases such as Oracle). |
---|
| 2610 | |
---|
| 2611 | This object is constructed from the ``alias()`` module level |
---|
| 2612 | function as well as the ``alias()`` method available on all |
---|
| 2613 | ``FromClause`` subclasses. |
---|
| 2614 | |
---|
| 2615 | """ |
---|
| 2616 | |
---|
| 2617 | __visit_name__ = 'alias' |
---|
| 2618 | named_with_column = True |
---|
| 2619 | |
---|
| 2620 | def __init__(self, selectable, alias=None): |
---|
| 2621 | baseselectable = selectable |
---|
| 2622 | while isinstance(baseselectable, Alias): |
---|
| 2623 | baseselectable = baseselectable.element |
---|
| 2624 | self.original = baseselectable |
---|
| 2625 | self.supports_execution = baseselectable.supports_execution |
---|
| 2626 | if self.supports_execution: |
---|
| 2627 | self._autocommit = baseselectable._autocommit |
---|
| 2628 | self.element = selectable |
---|
| 2629 | if alias is None: |
---|
| 2630 | if self.original.named_with_column: |
---|
| 2631 | alias = getattr(self.original, 'name', None) |
---|
| 2632 | alias = _generated_label('%%(%d %s)s' % (id(self), alias or 'anon')) |
---|
| 2633 | self.name = alias |
---|
| 2634 | |
---|
| 2635 | @property |
---|
| 2636 | def description(self): |
---|
| 2637 | return self.name.encode('ascii', 'backslashreplace') |
---|
| 2638 | |
---|
| 2639 | def as_scalar(self): |
---|
| 2640 | try: |
---|
| 2641 | return self.element.as_scalar() |
---|
| 2642 | except AttributeError: |
---|
| 2643 | raise AttributeError("Element %s does not support 'as_scalar()'" % self.element) |
---|
| 2644 | |
---|
| 2645 | def is_derived_from(self, fromclause): |
---|
| 2646 | if fromclause in self._cloned_set: |
---|
| 2647 | return True |
---|
| 2648 | return self.element.is_derived_from(fromclause) |
---|
| 2649 | |
---|
| 2650 | def _populate_column_collection(self): |
---|
| 2651 | for col in self.element.columns: |
---|
| 2652 | col._make_proxy(self) |
---|
| 2653 | |
---|
| 2654 | def _copy_internals(self, clone=_clone): |
---|
| 2655 | self._reset_exported() |
---|
| 2656 | self.element = _clone(self.element) |
---|
| 2657 | baseselectable = self.element |
---|
| 2658 | while isinstance(baseselectable, Alias): |
---|
| 2659 | baseselectable = baseselectable.selectable |
---|
| 2660 | self.original = baseselectable |
---|
| 2661 | |
---|
| 2662 | def get_children(self, column_collections=True, aliased_selectables=True, **kwargs): |
---|
| 2663 | if column_collections: |
---|
| 2664 | for c in self.c: |
---|
| 2665 | yield c |
---|
| 2666 | if aliased_selectables: |
---|
| 2667 | yield self.element |
---|
| 2668 | |
---|
| 2669 | @property |
---|
| 2670 | def _from_objects(self): |
---|
| 2671 | return [self] |
---|
| 2672 | |
---|
| 2673 | @property |
---|
| 2674 | def bind(self): |
---|
| 2675 | return self.element.bind |
---|
| 2676 | |
---|
| 2677 | class _Grouping(ColumnElement): |
---|
| 2678 | """Represent a grouping within a column expression""" |
---|
| 2679 | |
---|
| 2680 | __visit_name__ = 'grouping' |
---|
| 2681 | |
---|
| 2682 | def __init__(self, element): |
---|
| 2683 | self.element = element |
---|
| 2684 | self.type = getattr(element, 'type', None) |
---|
| 2685 | |
---|
| 2686 | @property |
---|
| 2687 | def key(self): |
---|
| 2688 | return self.element.key |
---|
| 2689 | |
---|
| 2690 | @property |
---|
| 2691 | def _label(self): |
---|
| 2692 | return getattr(self.element, '_label', None) or self.anon_label |
---|
| 2693 | |
---|
| 2694 | def _copy_internals(self, clone=_clone): |
---|
| 2695 | self.element = clone(self.element) |
---|
| 2696 | |
---|
| 2697 | def get_children(self, **kwargs): |
---|
| 2698 | return self.element, |
---|
| 2699 | |
---|
| 2700 | @property |
---|
| 2701 | def _from_objects(self): |
---|
| 2702 | return self.element._from_objects |
---|
| 2703 | |
---|
| 2704 | def __getattr__(self, attr): |
---|
| 2705 | return getattr(self.element, attr) |
---|
| 2706 | |
---|
| 2707 | def __getstate__(self): |
---|
| 2708 | return {'element':self.element, 'type':self.type} |
---|
| 2709 | |
---|
| 2710 | def __setstate__(self, state): |
---|
| 2711 | self.element = state['element'] |
---|
| 2712 | self.type = state['type'] |
---|
| 2713 | |
---|
| 2714 | class _FromGrouping(FromClause): |
---|
| 2715 | """Represent a grouping of a FROM clause""" |
---|
| 2716 | __visit_name__ = 'grouping' |
---|
| 2717 | |
---|
| 2718 | def __init__(self, element): |
---|
| 2719 | self.element = element |
---|
| 2720 | |
---|
| 2721 | @property |
---|
| 2722 | def columns(self): |
---|
| 2723 | return self.element.columns |
---|
| 2724 | |
---|
| 2725 | @property |
---|
| 2726 | def _hide_froms(self): |
---|
| 2727 | return self.element._hide_froms |
---|
| 2728 | |
---|
| 2729 | def get_children(self, **kwargs): |
---|
| 2730 | return self.element, |
---|
| 2731 | |
---|
| 2732 | def _copy_internals(self, clone=_clone): |
---|
| 2733 | self.element = clone(self.element) |
---|
| 2734 | |
---|
| 2735 | @property |
---|
| 2736 | def _from_objects(self): |
---|
| 2737 | return self.element._from_objects |
---|
| 2738 | |
---|
| 2739 | def __getattr__(self, attr): |
---|
| 2740 | return getattr(self.element, attr) |
---|
| 2741 | |
---|
| 2742 | def __getstate__(self): |
---|
| 2743 | return {'element':self.element} |
---|
| 2744 | |
---|
| 2745 | def __setstate__(self, state): |
---|
| 2746 | self.element = state['element'] |
---|
| 2747 | |
---|
| 2748 | class _Label(ColumnElement): |
---|
| 2749 | """Represents a column label (AS). |
---|
| 2750 | |
---|
| 2751 | Represent a label, as typically applied to any column-level |
---|
| 2752 | element using the ``AS`` sql keyword. |
---|
| 2753 | |
---|
| 2754 | This object is constructed from the ``label()`` module level |
---|
| 2755 | function as well as the ``label()`` method available on all |
---|
| 2756 | ``ColumnElement`` subclasses. |
---|
| 2757 | |
---|
| 2758 | """ |
---|
| 2759 | |
---|
| 2760 | __visit_name__ = 'label' |
---|
| 2761 | |
---|
| 2762 | def __init__(self, name, element, type_=None): |
---|
| 2763 | while isinstance(element, _Label): |
---|
| 2764 | element = element.element |
---|
| 2765 | self.name = self.key = self._label = name or _generated_label("%%(%d %s)s" % (id(self), getattr(element, 'name', 'anon'))) |
---|
| 2766 | self._element = element |
---|
| 2767 | self._type = type_ |
---|
| 2768 | self.quote = element.quote |
---|
| 2769 | |
---|
| 2770 | @util.memoized_property |
---|
| 2771 | def type(self): |
---|
| 2772 | return sqltypes.to_instance(self._type or getattr(self._element, 'type', None)) |
---|
| 2773 | |
---|
| 2774 | @util.memoized_property |
---|
| 2775 | def element(self): |
---|
| 2776 | return self._element.self_group(against=operators.as_) |
---|
| 2777 | |
---|
| 2778 | def _proxy_attr(name): |
---|
| 2779 | get = attrgetter(name) |
---|
| 2780 | def attr(self): |
---|
| 2781 | return get(self.element) |
---|
| 2782 | return property(attr) |
---|
| 2783 | |
---|
| 2784 | proxies = _proxy_attr('proxies') |
---|
| 2785 | base_columns = _proxy_attr('base_columns') |
---|
| 2786 | proxy_set = _proxy_attr('proxy_set') |
---|
| 2787 | primary_key = _proxy_attr('primary_key') |
---|
| 2788 | foreign_keys = _proxy_attr('foreign_keys') |
---|
| 2789 | |
---|
| 2790 | def get_children(self, **kwargs): |
---|
| 2791 | return self.element, |
---|
| 2792 | |
---|
| 2793 | def _copy_internals(self, clone=_clone): |
---|
| 2794 | self.element = clone(self.element) |
---|
| 2795 | |
---|
| 2796 | @property |
---|
| 2797 | def _from_objects(self): |
---|
| 2798 | return self.element._from_objects |
---|
| 2799 | |
---|
| 2800 | def _make_proxy(self, selectable, name = None): |
---|
| 2801 | if isinstance(self.element, (Selectable, ColumnElement)): |
---|
| 2802 | e = self.element._make_proxy(selectable, name=self.name) |
---|
| 2803 | else: |
---|
| 2804 | e = column(self.name)._make_proxy(selectable=selectable) |
---|
| 2805 | e.proxies.append(self) |
---|
| 2806 | return e |
---|
| 2807 | |
---|
| 2808 | class ColumnClause(_Immutable, ColumnElement): |
---|
| 2809 | """Represents a generic column expression from any textual string. |
---|
| 2810 | |
---|
| 2811 | This includes columns associated with tables, aliases and select |
---|
| 2812 | statements, but also any arbitrary text. May or may not be bound |
---|
| 2813 | to an underlying ``Selectable``. ``ColumnClause`` is usually |
---|
| 2814 | created publically via the ``column()`` function or the |
---|
| 2815 | ``literal_column()`` function. |
---|
| 2816 | |
---|
| 2817 | text |
---|
| 2818 | the text of the element. |
---|
| 2819 | |
---|
| 2820 | selectable |
---|
| 2821 | parent selectable. |
---|
| 2822 | |
---|
| 2823 | type |
---|
| 2824 | ``TypeEngine`` object which can associate this ``ColumnClause`` |
---|
| 2825 | with a type. |
---|
| 2826 | |
---|
| 2827 | is_literal |
---|
| 2828 | if True, the ``ColumnClause`` is assumed to be an exact |
---|
| 2829 | expression that will be delivered to the output with no quoting |
---|
| 2830 | rules applied regardless of case sensitive settings. the |
---|
| 2831 | ``literal_column()`` function is usually used to create such a |
---|
| 2832 | ``ColumnClause``. |
---|
| 2833 | |
---|
| 2834 | """ |
---|
| 2835 | __visit_name__ = 'column' |
---|
| 2836 | |
---|
| 2837 | def __init__(self, text, selectable=None, type_=None, is_literal=False): |
---|
| 2838 | self.key = self.name = text |
---|
| 2839 | self.table = selectable |
---|
| 2840 | self.type = sqltypes.to_instance(type_) |
---|
| 2841 | self.is_literal = is_literal |
---|
| 2842 | |
---|
| 2843 | @util.memoized_property |
---|
| 2844 | def description(self): |
---|
| 2845 | return self.name.encode('ascii', 'backslashreplace') |
---|
| 2846 | |
---|
| 2847 | @util.memoized_property |
---|
| 2848 | def _label(self): |
---|
| 2849 | if self.is_literal: |
---|
| 2850 | return None |
---|
| 2851 | |
---|
| 2852 | elif self.table and self.table.named_with_column: |
---|
| 2853 | if getattr(self.table, 'schema', None): |
---|
| 2854 | label = self.table.schema + "_" + \ |
---|
| 2855 | _escape_for_generated(self.table.name) + "_" + \ |
---|
| 2856 | _escape_for_generated(self.name) |
---|
| 2857 | else: |
---|
| 2858 | label = _escape_for_generated(self.table.name) + "_" + \ |
---|
| 2859 | _escape_for_generated(self.name) |
---|
| 2860 | |
---|
| 2861 | if label in self.table.c: |
---|
| 2862 | # TODO: coverage does not seem to be present for this |
---|
| 2863 | _label = label |
---|
| 2864 | counter = 1 |
---|
| 2865 | while _label in self.table.c: |
---|
| 2866 | _label = label + "_" + str(counter) |
---|
| 2867 | counter += 1 |
---|
| 2868 | label = _label |
---|
| 2869 | return _generated_label(label) |
---|
| 2870 | |
---|
| 2871 | else: |
---|
| 2872 | return self.name |
---|
| 2873 | |
---|
| 2874 | def label(self, name): |
---|
| 2875 | if name is None: |
---|
| 2876 | return self |
---|
| 2877 | else: |
---|
| 2878 | return super(ColumnClause, self).label(name) |
---|
| 2879 | |
---|
| 2880 | @property |
---|
| 2881 | def _from_objects(self): |
---|
| 2882 | if self.table: |
---|
| 2883 | return [self.table] |
---|
| 2884 | else: |
---|
| 2885 | return [] |
---|
| 2886 | |
---|
| 2887 | def _bind_param(self, obj): |
---|
| 2888 | return _BindParamClause(self.name, obj, type_=self.type, unique=True) |
---|
| 2889 | |
---|
| 2890 | def _make_proxy(self, selectable, name=None, attach=True): |
---|
| 2891 | # propagate the "is_literal" flag only if we are keeping our name, |
---|
| 2892 | # otherwise its considered to be a label |
---|
| 2893 | is_literal = self.is_literal and (name is None or name == self.name) |
---|
| 2894 | c = ColumnClause(name or self.name, selectable=selectable, type_=self.type, is_literal=is_literal) |
---|
| 2895 | c.proxies = [self] |
---|
| 2896 | if attach: |
---|
| 2897 | selectable.columns[c.name] = c |
---|
| 2898 | return c |
---|
| 2899 | |
---|
| 2900 | def _compare_type(self, obj): |
---|
| 2901 | return self.type |
---|
| 2902 | |
---|
| 2903 | class TableClause(_Immutable, FromClause): |
---|
| 2904 | """Represents a "table" construct. |
---|
| 2905 | |
---|
| 2906 | Note that this represents tables only as another syntactical |
---|
| 2907 | construct within SQL expressions; it does not provide schema-level |
---|
| 2908 | functionality. |
---|
| 2909 | |
---|
| 2910 | """ |
---|
| 2911 | |
---|
| 2912 | __visit_name__ = 'table' |
---|
| 2913 | |
---|
| 2914 | named_with_column = True |
---|
| 2915 | |
---|
| 2916 | def __init__(self, name, *columns): |
---|
| 2917 | super(TableClause, self).__init__() |
---|
| 2918 | self.name = self.fullname = name |
---|
| 2919 | self._columns = ColumnCollection() |
---|
| 2920 | self._primary_key = ColumnSet() |
---|
| 2921 | self._foreign_keys = set() |
---|
| 2922 | for c in columns: |
---|
| 2923 | self.append_column(c) |
---|
| 2924 | |
---|
| 2925 | def _export_columns(self): |
---|
| 2926 | raise NotImplementedError() |
---|
| 2927 | |
---|
| 2928 | @util.memoized_property |
---|
| 2929 | def description(self): |
---|
| 2930 | return self.name.encode('ascii', 'backslashreplace') |
---|
| 2931 | |
---|
| 2932 | def append_column(self, c): |
---|
| 2933 | self._columns[c.name] = c |
---|
| 2934 | c.table = self |
---|
| 2935 | |
---|
| 2936 | def get_children(self, column_collections=True, **kwargs): |
---|
| 2937 | if column_collections: |
---|
| 2938 | return [c for c in self.c] |
---|
| 2939 | else: |
---|
| 2940 | return [] |
---|
| 2941 | |
---|
| 2942 | def count(self, whereclause=None, **params): |
---|
| 2943 | if self.primary_key: |
---|
| 2944 | col = list(self.primary_key)[0] |
---|
| 2945 | else: |
---|
| 2946 | col = list(self.columns)[0] |
---|
| 2947 | return select([func.count(col).label('tbl_row_count')], whereclause, from_obj=[self], **params) |
---|
| 2948 | |
---|
| 2949 | def insert(self, values=None, inline=False, **kwargs): |
---|
| 2950 | """Generate an :func:`~sqlalchemy.sql.expression.insert()` construct.""" |
---|
| 2951 | |
---|
| 2952 | return insert(self, values=values, inline=inline, **kwargs) |
---|
| 2953 | |
---|
| 2954 | def update(self, whereclause=None, values=None, inline=False, **kwargs): |
---|
| 2955 | """Generate an :func:`~sqlalchemy.sql.expression.update()` construct.""" |
---|
| 2956 | |
---|
| 2957 | return update(self, whereclause=whereclause, values=values, inline=inline, **kwargs) |
---|
| 2958 | |
---|
| 2959 | def delete(self, whereclause=None, **kwargs): |
---|
| 2960 | """Generate a :func:`~sqlalchemy.sql.expression.delete()` construct.""" |
---|
| 2961 | |
---|
| 2962 | return delete(self, whereclause, **kwargs) |
---|
| 2963 | |
---|
| 2964 | @property |
---|
| 2965 | def _from_objects(self): |
---|
| 2966 | return [self] |
---|
| 2967 | |
---|
| 2968 | @util.decorator |
---|
| 2969 | def _generative(fn, *args, **kw): |
---|
| 2970 | """Mark a method as generative.""" |
---|
| 2971 | |
---|
| 2972 | self = args[0]._generate() |
---|
| 2973 | fn(self, *args[1:], **kw) |
---|
| 2974 | return self |
---|
| 2975 | |
---|
| 2976 | class _SelectBaseMixin(object): |
---|
| 2977 | """Base class for ``Select`` and ``CompoundSelects``.""" |
---|
| 2978 | |
---|
| 2979 | supports_execution = True |
---|
| 2980 | |
---|
| 2981 | def __init__(self, |
---|
| 2982 | use_labels=False, |
---|
| 2983 | for_update=False, |
---|
| 2984 | limit=None, |
---|
| 2985 | offset=None, |
---|
| 2986 | order_by=None, |
---|
| 2987 | group_by=None, |
---|
| 2988 | bind=None, |
---|
| 2989 | autocommit=False): |
---|
| 2990 | self.use_labels = use_labels |
---|
| 2991 | self.for_update = for_update |
---|
| 2992 | self._autocommit = autocommit |
---|
| 2993 | self._limit = limit |
---|
| 2994 | self._offset = offset |
---|
| 2995 | self._bind = bind |
---|
| 2996 | |
---|
| 2997 | self._order_by_clause = ClauseList(*util.to_list(order_by) or []) |
---|
| 2998 | self._group_by_clause = ClauseList(*util.to_list(group_by) or []) |
---|
| 2999 | |
---|
| 3000 | def as_scalar(self): |
---|
| 3001 | """return a 'scalar' representation of this selectable, which can be used |
---|
| 3002 | as a column expression. |
---|
| 3003 | |
---|
| 3004 | Typically, a select statement which has only one column in its columns clause |
---|
| 3005 | is eligible to be used as a scalar expression. |
---|
| 3006 | |
---|
| 3007 | The returned object is an instance of :class:`~sqlalchemy.sql.expression._ScalarSelect`. |
---|
| 3008 | |
---|
| 3009 | """ |
---|
| 3010 | return _ScalarSelect(self) |
---|
| 3011 | |
---|
| 3012 | @_generative |
---|
| 3013 | def apply_labels(self): |
---|
| 3014 | """return a new selectable with the 'use_labels' flag set to True. |
---|
| 3015 | |
---|
| 3016 | This will result in column expressions being generated using labels against their table |
---|
| 3017 | name, such as "SELECT somecolumn AS tablename_somecolumn". This allows selectables which |
---|
| 3018 | contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts |
---|
| 3019 | among the individual FROM clauses. |
---|
| 3020 | |
---|
| 3021 | """ |
---|
| 3022 | self.use_labels = True |
---|
| 3023 | |
---|
| 3024 | def label(self, name): |
---|
| 3025 | """return a 'scalar' representation of this selectable, embedded as a subquery |
---|
| 3026 | with a label. |
---|
| 3027 | |
---|
| 3028 | See also ``as_scalar()``. |
---|
| 3029 | |
---|
| 3030 | """ |
---|
| 3031 | return self.as_scalar().label(name) |
---|
| 3032 | |
---|
| 3033 | @_generative |
---|
| 3034 | def autocommit(self): |
---|
| 3035 | """return a new selectable with the 'autocommit' flag set to True.""" |
---|
| 3036 | |
---|
| 3037 | self._autocommit = True |
---|
| 3038 | |
---|
| 3039 | def _generate(self): |
---|
| 3040 | s = self.__class__.__new__(self.__class__) |
---|
| 3041 | s.__dict__ = self.__dict__.copy() |
---|
| 3042 | s._reset_exported() |
---|
| 3043 | return s |
---|
| 3044 | |
---|
| 3045 | @_generative |
---|
| 3046 | def limit(self, limit): |
---|
| 3047 | """return a new selectable with the given LIMIT criterion applied.""" |
---|
| 3048 | |
---|
| 3049 | self._limit = limit |
---|
| 3050 | |
---|
| 3051 | @_generative |
---|
| 3052 | def offset(self, offset): |
---|
| 3053 | """return a new selectable with the given OFFSET criterion applied.""" |
---|
| 3054 | |
---|
| 3055 | self._offset = offset |
---|
| 3056 | |
---|
| 3057 | @_generative |
---|
| 3058 | def order_by(self, *clauses): |
---|
| 3059 | """return a new selectable with the given list of ORDER BY criterion applied. |
---|
| 3060 | |
---|
| 3061 | The criterion will be appended to any pre-existing ORDER BY criterion. |
---|
| 3062 | |
---|
| 3063 | """ |
---|
| 3064 | self.append_order_by(*clauses) |
---|
| 3065 | |
---|
| 3066 | @_generative |
---|
| 3067 | def group_by(self, *clauses): |
---|
| 3068 | """return a new selectable with the given list of GROUP BY criterion applied. |
---|
| 3069 | |
---|
| 3070 | The criterion will be appended to any pre-existing GROUP BY criterion. |
---|
| 3071 | |
---|
| 3072 | """ |
---|
| 3073 | self.append_group_by(*clauses) |
---|
| 3074 | |
---|
| 3075 | def append_order_by(self, *clauses): |
---|
| 3076 | """Append the given ORDER BY criterion applied to this selectable. |
---|
| 3077 | |
---|
| 3078 | The criterion will be appended to any pre-existing ORDER BY criterion. |
---|
| 3079 | |
---|
| 3080 | """ |
---|
| 3081 | if len(clauses) == 1 and clauses[0] is None: |
---|
| 3082 | self._order_by_clause = ClauseList() |
---|
| 3083 | else: |
---|
| 3084 | if getattr(self, '_order_by_clause', None): |
---|
| 3085 | clauses = list(self._order_by_clause) + list(clauses) |
---|
| 3086 | self._order_by_clause = ClauseList(*clauses) |
---|
| 3087 | |
---|
| 3088 | def append_group_by(self, *clauses): |
---|
| 3089 | """Append the given GROUP BY criterion applied to this selectable. |
---|
| 3090 | |
---|
| 3091 | The criterion will be appended to any pre-existing GROUP BY criterion. |
---|
| 3092 | |
---|
| 3093 | """ |
---|
| 3094 | if len(clauses) == 1 and clauses[0] is None: |
---|
| 3095 | self._group_by_clause = ClauseList() |
---|
| 3096 | else: |
---|
| 3097 | if getattr(self, '_group_by_clause', None): |
---|
| 3098 | clauses = list(self._group_by_clause) + list(clauses) |
---|
| 3099 | self._group_by_clause = ClauseList(*clauses) |
---|
| 3100 | |
---|
| 3101 | @property |
---|
| 3102 | def _from_objects(self): |
---|
| 3103 | return [self] |
---|
| 3104 | |
---|
| 3105 | |
---|
| 3106 | class _ScalarSelect(_Grouping): |
---|
| 3107 | _from_objects = [] |
---|
| 3108 | |
---|
| 3109 | def __init__(self, element): |
---|
| 3110 | self.element = element |
---|
| 3111 | cols = list(element.c) |
---|
| 3112 | if len(cols) != 1: |
---|
| 3113 | raise exc.InvalidRequestError("Scalar select can only be created " |
---|
| 3114 | "from a Select object that has exactly one column expression.") |
---|
| 3115 | self.type = cols[0].type |
---|
| 3116 | |
---|
| 3117 | @property |
---|
| 3118 | def columns(self): |
---|
| 3119 | raise exc.InvalidRequestError("Scalar Select expression has no columns; " |
---|
| 3120 | "use this object directly within a column-level expression.") |
---|
| 3121 | c = columns |
---|
| 3122 | |
---|
| 3123 | def self_group(self, **kwargs): |
---|
| 3124 | return self |
---|
| 3125 | |
---|
| 3126 | def _make_proxy(self, selectable, name): |
---|
| 3127 | return list(self.inner_columns)[0]._make_proxy(selectable, name) |
---|
| 3128 | |
---|
| 3129 | class CompoundSelect(_SelectBaseMixin, FromClause): |
---|
| 3130 | """Forms the basis of ``UNION``, ``UNION ALL``, and other SELECT-based set operations.""" |
---|
| 3131 | |
---|
| 3132 | __visit_name__ = 'compound_select' |
---|
| 3133 | |
---|
| 3134 | def __init__(self, keyword, *selects, **kwargs): |
---|
| 3135 | self._should_correlate = kwargs.pop('correlate', False) |
---|
| 3136 | self.keyword = keyword |
---|
| 3137 | self.selects = [] |
---|
| 3138 | |
---|
| 3139 | numcols = None |
---|
| 3140 | |
---|
| 3141 | # some DBs do not like ORDER BY in the inner queries of a UNION, etc. |
---|
| 3142 | for n, s in enumerate(selects): |
---|
| 3143 | s = _clause_element_as_expr(s) |
---|
| 3144 | |
---|
| 3145 | if not numcols: |
---|
| 3146 | numcols = len(s.c) |
---|
| 3147 | elif len(s.c) != numcols: |
---|
| 3148 | raise exc.ArgumentError( |
---|
| 3149 | "All selectables passed to CompoundSelect must " |
---|
| 3150 | "have identical numbers of columns; select #%d has %d columns, select #%d has %d" % |
---|
| 3151 | (1, len(self.selects[0].c), n+1, len(s.c)) |
---|
| 3152 | ) |
---|
| 3153 | |
---|
| 3154 | # unions group from left to right, so don't group first select |
---|
| 3155 | if n: |
---|
| 3156 | self.selects.append(s.self_group(self)) |
---|
| 3157 | else: |
---|
| 3158 | self.selects.append(s) |
---|
| 3159 | |
---|
| 3160 | _SelectBaseMixin.__init__(self, **kwargs) |
---|
| 3161 | |
---|
| 3162 | def self_group(self, against=None): |
---|
| 3163 | return _FromGrouping(self) |
---|
| 3164 | |
---|
| 3165 | def is_derived_from(self, fromclause): |
---|
| 3166 | for s in self.selects: |
---|
| 3167 | if s.is_derived_from(fromclause): |
---|
| 3168 | return True |
---|
| 3169 | return False |
---|
| 3170 | |
---|
| 3171 | def _populate_column_collection(self): |
---|
| 3172 | for cols in zip(*[s.c for s in self.selects]): |
---|
| 3173 | # this is a slightly hacky thing - the union exports a column that |
---|
| 3174 | # resembles just that of the *first* selectable. to get at a "composite" column, |
---|
| 3175 | # particularly foreign keys, you have to dig through the proxies collection |
---|
| 3176 | # which we generate below. We may want to improve upon this, |
---|
| 3177 | # such as perhaps _make_proxy can accept a list of other columns that |
---|
| 3178 | # are "shared" - schema.column can then copy all the ForeignKeys in. |
---|
| 3179 | # this would allow the union() to have all those fks too. |
---|
| 3180 | proxy = cols[0]._make_proxy( |
---|
| 3181 | self, name=self.use_labels and cols[0]._label or None) |
---|
| 3182 | |
---|
| 3183 | # hand-construct the "proxies" collection to include all derived columns |
---|
| 3184 | # place a 'weight' annotation corresponding to how low in the list of |
---|
| 3185 | # select()s the column occurs, so that the corresponding_column() operation |
---|
| 3186 | # can resolve conflicts |
---|
| 3187 | proxy.proxies = [c._annotate({'weight':i + 1}) for i, c in enumerate(cols)] |
---|
| 3188 | |
---|
| 3189 | def _copy_internals(self, clone=_clone): |
---|
| 3190 | self._reset_exported() |
---|
| 3191 | self.selects = [clone(s) for s in self.selects] |
---|
| 3192 | if hasattr(self, '_col_map'): |
---|
| 3193 | del self._col_map |
---|
| 3194 | for attr in ('_order_by_clause', '_group_by_clause'): |
---|
| 3195 | if getattr(self, attr) is not None: |
---|
| 3196 | setattr(self, attr, clone(getattr(self, attr))) |
---|
| 3197 | |
---|
| 3198 | def get_children(self, column_collections=True, **kwargs): |
---|
| 3199 | return (column_collections and list(self.c) or []) + \ |
---|
| 3200 | [self._order_by_clause, self._group_by_clause] + list(self.selects) |
---|
| 3201 | |
---|
| 3202 | def bind(self): |
---|
| 3203 | if self._bind: |
---|
| 3204 | return self._bind |
---|
| 3205 | for s in self.selects: |
---|
| 3206 | e = s.bind |
---|
| 3207 | if e: |
---|
| 3208 | return e |
---|
| 3209 | else: |
---|
| 3210 | return None |
---|
| 3211 | def _set_bind(self, bind): |
---|
| 3212 | self._bind = bind |
---|
| 3213 | bind = property(bind, _set_bind) |
---|
| 3214 | |
---|
| 3215 | class Select(_SelectBaseMixin, FromClause): |
---|
| 3216 | """Represents a ``SELECT`` statement. |
---|
| 3217 | |
---|
| 3218 | Select statements support appendable clauses, as well as the |
---|
| 3219 | ability to execute themselves and return a result set. |
---|
| 3220 | |
---|
| 3221 | """ |
---|
| 3222 | |
---|
| 3223 | __visit_name__ = 'select' |
---|
| 3224 | |
---|
| 3225 | def __init__(self, columns, whereclause=None, from_obj=None, distinct=False, having=None, correlate=True, prefixes=None, **kwargs): |
---|
| 3226 | """Construct a Select object. |
---|
| 3227 | |
---|
| 3228 | The public constructor for Select is the |
---|
| 3229 | :func:`~sqlalchemy.sql.expression.select` function; see that function for |
---|
| 3230 | argument descriptions. |
---|
| 3231 | |
---|
| 3232 | Additional generative and mutator methods are available on the |
---|
| 3233 | :class:`~sqlalchemy.sql.expression._SelectBaseMixin` superclass. |
---|
| 3234 | |
---|
| 3235 | """ |
---|
| 3236 | self._should_correlate = correlate |
---|
| 3237 | self._distinct = distinct |
---|
| 3238 | |
---|
| 3239 | self._correlate = set() |
---|
| 3240 | self._froms = util.OrderedSet() |
---|
| 3241 | |
---|
| 3242 | if columns: |
---|
| 3243 | self._raw_columns = [ |
---|
| 3244 | isinstance(c, _ScalarSelect) and c.self_group(against=operators.comma_op) or c |
---|
| 3245 | for c in |
---|
| 3246 | [_literal_as_column(c) for c in columns] |
---|
| 3247 | ] |
---|
| 3248 | |
---|
| 3249 | self._froms.update(_from_objects(*self._raw_columns)) |
---|
| 3250 | else: |
---|
| 3251 | self._raw_columns = [] |
---|
| 3252 | |
---|
| 3253 | if whereclause: |
---|
| 3254 | self._whereclause = _literal_as_text(whereclause) |
---|
| 3255 | self._froms.update(_from_objects(self._whereclause)) |
---|
| 3256 | else: |
---|
| 3257 | self._whereclause = None |
---|
| 3258 | |
---|
| 3259 | if from_obj: |
---|
| 3260 | self._froms.update( |
---|
| 3261 | _is_literal(f) and _TextClause(f) or f |
---|
| 3262 | for f in util.to_list(from_obj)) |
---|
| 3263 | |
---|
| 3264 | if having: |
---|
| 3265 | self._having = _literal_as_text(having) |
---|
| 3266 | else: |
---|
| 3267 | self._having = None |
---|
| 3268 | |
---|
| 3269 | if prefixes: |
---|
| 3270 | self._prefixes = [_literal_as_text(p) for p in prefixes] |
---|
| 3271 | else: |
---|
| 3272 | self._prefixes = [] |
---|
| 3273 | |
---|
| 3274 | _SelectBaseMixin.__init__(self, **kwargs) |
---|
| 3275 | |
---|
| 3276 | def _get_display_froms(self, existing_froms=None): |
---|
| 3277 | """Return the full list of 'from' clauses to be displayed. |
---|
| 3278 | |
---|
| 3279 | Takes into account a set of existing froms which may be |
---|
| 3280 | rendered in the FROM clause of enclosing selects; this Select |
---|
| 3281 | may want to leave those absent if it is automatically |
---|
| 3282 | correlating. |
---|
| 3283 | |
---|
| 3284 | """ |
---|
| 3285 | froms = self._froms |
---|
| 3286 | |
---|
| 3287 | toremove = itertools.chain(*[f._hide_froms for f in froms]) |
---|
| 3288 | if toremove: |
---|
| 3289 | froms = froms.difference(toremove) |
---|
| 3290 | |
---|
| 3291 | if len(froms) > 1 or self._correlate: |
---|
| 3292 | if self._correlate: |
---|
| 3293 | froms = froms.difference(_cloned_intersection(froms, self._correlate)) |
---|
| 3294 | |
---|
| 3295 | if self._should_correlate and existing_froms: |
---|
| 3296 | froms = froms.difference(_cloned_intersection(froms, existing_froms)) |
---|
| 3297 | |
---|
| 3298 | if not len(froms): |
---|
| 3299 | raise exc.InvalidRequestError( |
---|
| 3300 | "Select statement '%s' returned no FROM clauses " |
---|
| 3301 | "due to auto-correlation; specify correlate(<tables>) " |
---|
| 3302 | "to control correlation manually." % self) |
---|
| 3303 | |
---|
| 3304 | return froms |
---|
| 3305 | |
---|
| 3306 | @property |
---|
| 3307 | def froms(self): |
---|
| 3308 | """Return the displayed list of FromClause elements.""" |
---|
| 3309 | |
---|
| 3310 | return self._get_display_froms() |
---|
| 3311 | |
---|
| 3312 | @property |
---|
| 3313 | def type(self): |
---|
| 3314 | raise exc.InvalidRequestError("Select objects don't have a type. " |
---|
| 3315 | "Call as_scalar() on this Select object " |
---|
| 3316 | "to return a 'scalar' version of this Select.") |
---|
| 3317 | |
---|
| 3318 | @util.memoized_instancemethod |
---|
| 3319 | def locate_all_froms(self): |
---|
| 3320 | """return a Set of all FromClause elements referenced by this Select. |
---|
| 3321 | |
---|
| 3322 | This set is a superset of that returned by the ``froms`` property, which |
---|
| 3323 | is specifically for those FromClause elements that would actually be rendered. |
---|
| 3324 | |
---|
| 3325 | """ |
---|
| 3326 | return self._froms.union(_from_objects(*list(self._froms))) |
---|
| 3327 | |
---|
| 3328 | @property |
---|
| 3329 | def inner_columns(self): |
---|
| 3330 | """an iterator of all ColumnElement expressions which would |
---|
| 3331 | be rendered into the columns clause of the resulting SELECT statement. |
---|
| 3332 | |
---|
| 3333 | """ |
---|
| 3334 | |
---|
| 3335 | return itertools.chain(*[c._select_iterable for c in self._raw_columns]) |
---|
| 3336 | |
---|
| 3337 | def is_derived_from(self, fromclause): |
---|
| 3338 | if self in fromclause._cloned_set: |
---|
| 3339 | return True |
---|
| 3340 | |
---|
| 3341 | for f in self.locate_all_froms(): |
---|
| 3342 | if f.is_derived_from(fromclause): |
---|
| 3343 | return True |
---|
| 3344 | return False |
---|
| 3345 | |
---|
| 3346 | def _copy_internals(self, clone=_clone): |
---|
| 3347 | self._reset_exported() |
---|
| 3348 | from_cloned = dict((f, clone(f)) |
---|
| 3349 | for f in self._froms.union(self._correlate)) |
---|
| 3350 | self._froms = set(from_cloned[f] for f in self._froms) |
---|
| 3351 | self._correlate = set(from_cloned[f] for f in self._correlate) |
---|
| 3352 | self._raw_columns = [clone(c) for c in self._raw_columns] |
---|
| 3353 | for attr in ('_whereclause', '_having', '_order_by_clause', '_group_by_clause'): |
---|
| 3354 | if getattr(self, attr) is not None: |
---|
| 3355 | setattr(self, attr, clone(getattr(self, attr))) |
---|
| 3356 | |
---|
| 3357 | def get_children(self, column_collections=True, **kwargs): |
---|
| 3358 | """return child elements as per the ClauseElement specification.""" |
---|
| 3359 | |
---|
| 3360 | return (column_collections and list(self.columns) or []) + \ |
---|
| 3361 | self._raw_columns + list(self._froms) + \ |
---|
| 3362 | [x for x in (self._whereclause, self._having, self._order_by_clause, self._group_by_clause) if x is not None] |
---|
| 3363 | |
---|
| 3364 | @_generative |
---|
| 3365 | def column(self, column): |
---|
| 3366 | """return a new select() construct with the given column expression added to its columns clause.""" |
---|
| 3367 | |
---|
| 3368 | column = _literal_as_column(column) |
---|
| 3369 | |
---|
| 3370 | if isinstance(column, _ScalarSelect): |
---|
| 3371 | column = column.self_group(against=operators.comma_op) |
---|
| 3372 | |
---|
| 3373 | self._raw_columns = self._raw_columns + [column] |
---|
| 3374 | self._froms = self._froms.union(_from_objects(column)) |
---|
| 3375 | |
---|
| 3376 | @_generative |
---|
| 3377 | def with_only_columns(self, columns): |
---|
| 3378 | """return a new select() construct with its columns clause replaced with the given columns.""" |
---|
| 3379 | |
---|
| 3380 | self._raw_columns = [ |
---|
| 3381 | isinstance(c, _ScalarSelect) and c.self_group(against=operators.comma_op) or c |
---|
| 3382 | for c in |
---|
| 3383 | [_literal_as_column(c) for c in columns] |
---|
| 3384 | ] |
---|
| 3385 | |
---|
| 3386 | @_generative |
---|
| 3387 | def where(self, whereclause): |
---|
| 3388 | """return a new select() construct with the given expression added to its WHERE clause, joined |
---|
| 3389 | to the existing clause via AND, if any.""" |
---|
| 3390 | |
---|
| 3391 | self.append_whereclause(whereclause) |
---|
| 3392 | |
---|
| 3393 | @_generative |
---|
| 3394 | def having(self, having): |
---|
| 3395 | """return a new select() construct with the given expression added to its HAVING clause, joined |
---|
| 3396 | to the existing clause via AND, if any.""" |
---|
| 3397 | |
---|
| 3398 | self.append_having(having) |
---|
| 3399 | |
---|
| 3400 | @_generative |
---|
| 3401 | def distinct(self): |
---|
| 3402 | """return a new select() construct which will apply DISTINCT to its columns clause.""" |
---|
| 3403 | |
---|
| 3404 | self._distinct = True |
---|
| 3405 | |
---|
| 3406 | @_generative |
---|
| 3407 | def prefix_with(self, clause): |
---|
| 3408 | """return a new select() construct which will apply the given expression to the start of its |
---|
| 3409 | columns clause, not using any commas.""" |
---|
| 3410 | |
---|
| 3411 | clause = _literal_as_text(clause) |
---|
| 3412 | self._prefixes = self._prefixes + [clause] |
---|
| 3413 | |
---|
| 3414 | @_generative |
---|
| 3415 | def select_from(self, fromclause): |
---|
| 3416 | """return a new select() construct with the given FROM expression applied to its list of |
---|
| 3417 | FROM objects.""" |
---|
| 3418 | |
---|
| 3419 | fromclause = _literal_as_text(fromclause) |
---|
| 3420 | self._froms = self._froms.union([fromclause]) |
---|
| 3421 | |
---|
| 3422 | @_generative |
---|
| 3423 | def correlate(self, *fromclauses): |
---|
| 3424 | """return a new select() construct which will correlate the given FROM clauses to that |
---|
| 3425 | of an enclosing select(), if a match is found. |
---|
| 3426 | |
---|
| 3427 | By "match", the given fromclause must be present in this select's list of FROM objects |
---|
| 3428 | and also present in an enclosing select's list of FROM objects. |
---|
| 3429 | |
---|
| 3430 | Calling this method turns off the select's default behavior of "auto-correlation". Normally, |
---|
| 3431 | select() auto-correlates all of its FROM clauses to those of an embedded select when |
---|
| 3432 | compiled. |
---|
| 3433 | |
---|
| 3434 | If the fromclause is None, correlation is disabled for the returned select(). |
---|
| 3435 | |
---|
| 3436 | """ |
---|
| 3437 | self._should_correlate = False |
---|
| 3438 | if fromclauses == (None,): |
---|
| 3439 | self._correlate = set() |
---|
| 3440 | else: |
---|
| 3441 | self._correlate = self._correlate.union(fromclauses) |
---|
| 3442 | |
---|
| 3443 | def append_correlation(self, fromclause): |
---|
| 3444 | """append the given correlation expression to this select() construct.""" |
---|
| 3445 | |
---|
| 3446 | self._should_correlate = False |
---|
| 3447 | self._correlate = self._correlate.union([fromclause]) |
---|
| 3448 | |
---|
| 3449 | def append_column(self, column): |
---|
| 3450 | """append the given column expression to the columns clause of this select() construct.""" |
---|
| 3451 | |
---|
| 3452 | column = _literal_as_column(column) |
---|
| 3453 | |
---|
| 3454 | if isinstance(column, _ScalarSelect): |
---|
| 3455 | column = column.self_group(against=operators.comma_op) |
---|
| 3456 | |
---|
| 3457 | self._raw_columns = self._raw_columns + [column] |
---|
| 3458 | self._froms = self._froms.union(_from_objects(column)) |
---|
| 3459 | self._reset_exported() |
---|
| 3460 | |
---|
| 3461 | def append_prefix(self, clause): |
---|
| 3462 | """append the given columns clause prefix expression to this select() construct.""" |
---|
| 3463 | |
---|
| 3464 | clause = _literal_as_text(clause) |
---|
| 3465 | self._prefixes = self._prefixes.union([clause]) |
---|
| 3466 | |
---|
| 3467 | def append_whereclause(self, whereclause): |
---|
| 3468 | """append the given expression to this select() construct's WHERE criterion. |
---|
| 3469 | |
---|
| 3470 | The expression will be joined to existing WHERE criterion via AND. |
---|
| 3471 | |
---|
| 3472 | """ |
---|
| 3473 | whereclause = _literal_as_text(whereclause) |
---|
| 3474 | self._froms = self._froms.union(_from_objects(whereclause)) |
---|
| 3475 | |
---|
| 3476 | if self._whereclause is not None: |
---|
| 3477 | self._whereclause = and_(self._whereclause, whereclause) |
---|
| 3478 | else: |
---|
| 3479 | self._whereclause = whereclause |
---|
| 3480 | |
---|
| 3481 | def append_having(self, having): |
---|
| 3482 | """append the given expression to this select() construct's HAVING criterion. |
---|
| 3483 | |
---|
| 3484 | The expression will be joined to existing HAVING criterion via AND. |
---|
| 3485 | |
---|
| 3486 | """ |
---|
| 3487 | if self._having is not None: |
---|
| 3488 | self._having = and_(self._having, _literal_as_text(having)) |
---|
| 3489 | else: |
---|
| 3490 | self._having = _literal_as_text(having) |
---|
| 3491 | |
---|
| 3492 | def append_from(self, fromclause): |
---|
| 3493 | """append the given FromClause expression to this select() construct's FROM clause. |
---|
| 3494 | |
---|
| 3495 | """ |
---|
| 3496 | if _is_literal(fromclause): |
---|
| 3497 | fromclause = _TextClause(fromclause) |
---|
| 3498 | |
---|
| 3499 | self._froms = self._froms.union([fromclause]) |
---|
| 3500 | |
---|
| 3501 | def __exportable_columns(self): |
---|
| 3502 | for column in self._raw_columns: |
---|
| 3503 | if isinstance(column, Selectable): |
---|
| 3504 | for co in column.columns: |
---|
| 3505 | yield co |
---|
| 3506 | elif isinstance(column, ColumnElement): |
---|
| 3507 | yield column |
---|
| 3508 | else: |
---|
| 3509 | continue |
---|
| 3510 | |
---|
| 3511 | def _populate_column_collection(self): |
---|
| 3512 | for c in self.__exportable_columns(): |
---|
| 3513 | c._make_proxy(self, name=self.use_labels and c._label or None) |
---|
| 3514 | |
---|
| 3515 | def self_group(self, against=None): |
---|
| 3516 | """return a 'grouping' construct as per the ClauseElement specification. |
---|
| 3517 | |
---|
| 3518 | This produces an element that can be embedded in an expression. Note that |
---|
| 3519 | this method is called automatically as needed when constructing expressions. |
---|
| 3520 | |
---|
| 3521 | """ |
---|
| 3522 | if isinstance(against, CompoundSelect): |
---|
| 3523 | return self |
---|
| 3524 | return _FromGrouping(self) |
---|
| 3525 | |
---|
| 3526 | def union(self, other, **kwargs): |
---|
| 3527 | """return a SQL UNION of this select() construct against the given selectable.""" |
---|
| 3528 | |
---|
| 3529 | return union(self, other, **kwargs) |
---|
| 3530 | |
---|
| 3531 | def union_all(self, other, **kwargs): |
---|
| 3532 | """return a SQL UNION ALL of this select() construct against the given selectable.""" |
---|
| 3533 | |
---|
| 3534 | return union_all(self, other, **kwargs) |
---|
| 3535 | |
---|
| 3536 | def except_(self, other, **kwargs): |
---|
| 3537 | """return a SQL EXCEPT of this select() construct against the given selectable.""" |
---|
| 3538 | |
---|
| 3539 | return except_(self, other, **kwargs) |
---|
| 3540 | |
---|
| 3541 | def except_all(self, other, **kwargs): |
---|
| 3542 | """return a SQL EXCEPT ALL of this select() construct against the given selectable.""" |
---|
| 3543 | |
---|
| 3544 | return except_all(self, other, **kwargs) |
---|
| 3545 | |
---|
| 3546 | def intersect(self, other, **kwargs): |
---|
| 3547 | """return a SQL INTERSECT of this select() construct against the given selectable.""" |
---|
| 3548 | |
---|
| 3549 | return intersect(self, other, **kwargs) |
---|
| 3550 | |
---|
| 3551 | def intersect_all(self, other, **kwargs): |
---|
| 3552 | """return a SQL INTERSECT ALL of this select() construct against the given selectable.""" |
---|
| 3553 | |
---|
| 3554 | return intersect_all(self, other, **kwargs) |
---|
| 3555 | |
---|
| 3556 | def bind(self): |
---|
| 3557 | if self._bind: |
---|
| 3558 | return self._bind |
---|
| 3559 | if not self._froms: |
---|
| 3560 | for c in self._raw_columns: |
---|
| 3561 | e = c.bind |
---|
| 3562 | if e: |
---|
| 3563 | self._bind = e |
---|
| 3564 | return e |
---|
| 3565 | else: |
---|
| 3566 | e = list(self._froms)[0].bind |
---|
| 3567 | if e: |
---|
| 3568 | self._bind = e |
---|
| 3569 | return e |
---|
| 3570 | |
---|
| 3571 | return None |
---|
| 3572 | |
---|
| 3573 | def _set_bind(self, bind): |
---|
| 3574 | self._bind = bind |
---|
| 3575 | bind = property(bind, _set_bind) |
---|
| 3576 | |
---|
| 3577 | class _UpdateBase(ClauseElement): |
---|
| 3578 | """Form the base for ``INSERT``, ``UPDATE``, and ``DELETE`` statements.""" |
---|
| 3579 | |
---|
| 3580 | __visit_name__ = 'update_base' |
---|
| 3581 | |
---|
| 3582 | supports_execution = True |
---|
| 3583 | _autocommit = True |
---|
| 3584 | |
---|
| 3585 | def _generate(self): |
---|
| 3586 | s = self.__class__.__new__(self.__class__) |
---|
| 3587 | s.__dict__ = self.__dict__.copy() |
---|
| 3588 | return s |
---|
| 3589 | |
---|
| 3590 | def _process_colparams(self, parameters): |
---|
| 3591 | if isinstance(parameters, (list, tuple)): |
---|
| 3592 | pp = {} |
---|
| 3593 | for i, c in enumerate(self.table.c): |
---|
| 3594 | pp[c.key] = parameters[i] |
---|
| 3595 | return pp |
---|
| 3596 | else: |
---|
| 3597 | return parameters |
---|
| 3598 | |
---|
| 3599 | def params(self, *arg, **kw): |
---|
| 3600 | raise NotImplementedError("params() is not supported for INSERT/UPDATE/DELETE statements." |
---|
| 3601 | " To set the values for an INSERT or UPDATE statement, use stmt.values(**parameters).") |
---|
| 3602 | |
---|
| 3603 | def bind(self): |
---|
| 3604 | return self._bind or self.table.bind |
---|
| 3605 | |
---|
| 3606 | def _set_bind(self, bind): |
---|
| 3607 | self._bind = bind |
---|
| 3608 | bind = property(bind, _set_bind) |
---|
| 3609 | |
---|
| 3610 | class _ValuesBase(_UpdateBase): |
---|
| 3611 | |
---|
| 3612 | __visit_name__ = 'values_base' |
---|
| 3613 | |
---|
| 3614 | def __init__(self, table, values): |
---|
| 3615 | self.table = table |
---|
| 3616 | self.parameters = self._process_colparams(values) |
---|
| 3617 | |
---|
| 3618 | @_generative |
---|
| 3619 | def values(self, *args, **kwargs): |
---|
| 3620 | """specify the VALUES clause for an INSERT statement, or the SET clause for an UPDATE. |
---|
| 3621 | |
---|
| 3622 | \**kwargs |
---|
| 3623 | key=<somevalue> arguments |
---|
| 3624 | |
---|
| 3625 | \*args |
---|
| 3626 | A single dictionary can be sent as the first positional argument. This allows |
---|
| 3627 | non-string based keys, such as Column objects, to be used. |
---|
| 3628 | |
---|
| 3629 | """ |
---|
| 3630 | if args: |
---|
| 3631 | v = args[0] |
---|
| 3632 | else: |
---|
| 3633 | v = {} |
---|
| 3634 | |
---|
| 3635 | if self.parameters is None: |
---|
| 3636 | self.parameters = self._process_colparams(v) |
---|
| 3637 | self.parameters.update(kwargs) |
---|
| 3638 | else: |
---|
| 3639 | self.parameters = self.parameters.copy() |
---|
| 3640 | self.parameters.update(self._process_colparams(v)) |
---|
| 3641 | self.parameters.update(kwargs) |
---|
| 3642 | |
---|
| 3643 | class Insert(_ValuesBase): |
---|
| 3644 | """Represent an INSERT construct. |
---|
| 3645 | |
---|
| 3646 | The ``Insert`` object is created using the :func:`insert()` function. |
---|
| 3647 | |
---|
| 3648 | """ |
---|
| 3649 | __visit_name__ = 'insert' |
---|
| 3650 | |
---|
| 3651 | def __init__(self, table, values=None, inline=False, bind=None, prefixes=None, **kwargs): |
---|
| 3652 | _ValuesBase.__init__(self, table, values) |
---|
| 3653 | self._bind = bind |
---|
| 3654 | self.select = None |
---|
| 3655 | self.inline = inline |
---|
| 3656 | if prefixes: |
---|
| 3657 | self._prefixes = [_literal_as_text(p) for p in prefixes] |
---|
| 3658 | else: |
---|
| 3659 | self._prefixes = [] |
---|
| 3660 | self.kwargs = kwargs |
---|
| 3661 | |
---|
| 3662 | def get_children(self, **kwargs): |
---|
| 3663 | if self.select is not None: |
---|
| 3664 | return self.select, |
---|
| 3665 | else: |
---|
| 3666 | return () |
---|
| 3667 | |
---|
| 3668 | def _copy_internals(self, clone=_clone): |
---|
| 3669 | # TODO: coverage |
---|
| 3670 | self.parameters = self.parameters.copy() |
---|
| 3671 | |
---|
| 3672 | @_generative |
---|
| 3673 | def prefix_with(self, clause): |
---|
| 3674 | """Add a word or expression between INSERT and INTO. Generative. |
---|
| 3675 | |
---|
| 3676 | If multiple prefixes are supplied, they will be separated with |
---|
| 3677 | spaces. |
---|
| 3678 | |
---|
| 3679 | """ |
---|
| 3680 | clause = _literal_as_text(clause) |
---|
| 3681 | self._prefixes = self._prefixes + [clause] |
---|
| 3682 | |
---|
| 3683 | class Update(_ValuesBase): |
---|
| 3684 | """Represent an Update construct. |
---|
| 3685 | |
---|
| 3686 | The ``Update`` object is created using the :func:`update()` function. |
---|
| 3687 | |
---|
| 3688 | """ |
---|
| 3689 | __visit_name__ = 'update' |
---|
| 3690 | |
---|
| 3691 | def __init__(self, table, whereclause, values=None, inline=False, bind=None, **kwargs): |
---|
| 3692 | _ValuesBase.__init__(self, table, values) |
---|
| 3693 | self._bind = bind |
---|
| 3694 | if whereclause: |
---|
| 3695 | self._whereclause = _literal_as_text(whereclause) |
---|
| 3696 | else: |
---|
| 3697 | self._whereclause = None |
---|
| 3698 | self.inline = inline |
---|
| 3699 | self.kwargs = kwargs |
---|
| 3700 | |
---|
| 3701 | def get_children(self, **kwargs): |
---|
| 3702 | if self._whereclause is not None: |
---|
| 3703 | return self._whereclause, |
---|
| 3704 | else: |
---|
| 3705 | return () |
---|
| 3706 | |
---|
| 3707 | def _copy_internals(self, clone=_clone): |
---|
| 3708 | # TODO: coverage |
---|
| 3709 | self._whereclause = clone(self._whereclause) |
---|
| 3710 | self.parameters = self.parameters.copy() |
---|
| 3711 | |
---|
| 3712 | @_generative |
---|
| 3713 | def where(self, whereclause): |
---|
| 3714 | """return a new update() construct with the given expression added to its WHERE clause, joined |
---|
| 3715 | to the existing clause via AND, if any.""" |
---|
| 3716 | |
---|
| 3717 | if self._whereclause is not None: |
---|
| 3718 | self._whereclause = and_(self._whereclause, _literal_as_text(whereclause)) |
---|
| 3719 | else: |
---|
| 3720 | self._whereclause = _literal_as_text(whereclause) |
---|
| 3721 | |
---|
| 3722 | |
---|
| 3723 | class Delete(_UpdateBase): |
---|
| 3724 | """Represent a DELETE construct. |
---|
| 3725 | |
---|
| 3726 | The ``Delete`` object is created using the :func:`delete()` function. |
---|
| 3727 | |
---|
| 3728 | """ |
---|
| 3729 | |
---|
| 3730 | __visit_name__ = 'delete' |
---|
| 3731 | |
---|
| 3732 | def __init__(self, table, whereclause, bind=None, **kwargs): |
---|
| 3733 | self._bind = bind |
---|
| 3734 | self.table = table |
---|
| 3735 | if whereclause: |
---|
| 3736 | self._whereclause = _literal_as_text(whereclause) |
---|
| 3737 | else: |
---|
| 3738 | self._whereclause = None |
---|
| 3739 | |
---|
| 3740 | self.kwargs = kwargs |
---|
| 3741 | |
---|
| 3742 | def get_children(self, **kwargs): |
---|
| 3743 | if self._whereclause is not None: |
---|
| 3744 | return self._whereclause, |
---|
| 3745 | else: |
---|
| 3746 | return () |
---|
| 3747 | |
---|
| 3748 | @_generative |
---|
| 3749 | def where(self, whereclause): |
---|
| 3750 | """Add the given WHERE clause to a newly returned delete construct.""" |
---|
| 3751 | |
---|
| 3752 | if self._whereclause is not None: |
---|
| 3753 | self._whereclause = and_(self._whereclause, _literal_as_text(whereclause)) |
---|
| 3754 | else: |
---|
| 3755 | self._whereclause = _literal_as_text(whereclause) |
---|
| 3756 | |
---|
| 3757 | def _copy_internals(self, clone=_clone): |
---|
| 3758 | # TODO: coverage |
---|
| 3759 | self._whereclause = clone(self._whereclause) |
---|
| 3760 | |
---|
| 3761 | class _IdentifiedClause(ClauseElement): |
---|
| 3762 | __visit_name__ = 'identified' |
---|
| 3763 | supports_execution = True |
---|
| 3764 | _autocommit = False |
---|
| 3765 | quote = None |
---|
| 3766 | |
---|
| 3767 | def __init__(self, ident): |
---|
| 3768 | self.ident = ident |
---|
| 3769 | |
---|
| 3770 | class SavepointClause(_IdentifiedClause): |
---|
| 3771 | __visit_name__ = 'savepoint' |
---|
| 3772 | |
---|
| 3773 | class RollbackToSavepointClause(_IdentifiedClause): |
---|
| 3774 | __visit_name__ = 'rollback_to_savepoint' |
---|
| 3775 | |
---|
| 3776 | class ReleaseSavepointClause(_IdentifiedClause): |
---|
| 3777 | __visit_name__ = 'release_savepoint' |
---|