Table 2.

Brief descriptions of SemMedDB tables

Name	Number of records	Content
CITATION	21 M	Metadata relevant for each PubMed citation
SENTENCE	119.1 M	Sentences from each PubMed citation
CONCEPT	1.3 M	Relevant information about UMLS Metathesaurus concepts
CONCEPT_SEMTYPE	1.5 M	One-to-many relationships between concepts and their semantic types from UMLS semantic network
PREDICATION	12.9 M	Unique predications
PREDICATION_ARGUMENT	27.5 M	Links between each predication and its subject and object contained in CONCEPT table
SENTENCE_PREDICATION	57.6 M	Links between a sentence and a predication extracted from it
PREDICATION_AGGREGATE	57.6 M	Convenience table that aggregates information from all of the tables above for more efficient access