* source code:

 http://code.google.com/p/rdffederator/

* step:

1.data download:

drugbank:  http://download.bio2rdf.org/release/3/drugbank/ drugbank.nq.gz 19-Dec-2014 13:23 52M

omim:  http://download.bio2rdf.org/release/3/omim/ omim.nq.gz 11-Nov-2014 03:50 124M

pharmgkb:  http://download.bio2rdf.org/release/3/pharmgkb/

2. ./generate_void.sh ../data/drugbank.nq drugbank_void.n3

    counting triples and properties
    counting types and entities
    counting distinct objects
    counting distinct subjects

drugbank: time taken: 91 seconds

omim: time taken: 411 seconds