Additional file 1: The relational database design of the PIANA database.
Information is kept in four types of tables: 1) biological entity tables (protein and interaction);
2) biological entity identifiers (UniProt entry, gene names, …); 3) biological entity information
(protein features tables and interaction properties). All information is linked to the internal
identifier of PIANA: proteinID (an index to all pairs [sequence, tax_id]).