Database links are a foundation for interoperability.

Several techniques are being introduced into the bioinformatics community to permit interoperation between molecular biology databases (DBs). The common factor to these approaches is the creation of links between entities in different DBs. Links can connect pieces of information about a single protein that are partitioned across multiple DBs, and can also encode relationships between different biological entities, such as relationships between an enzyme, its gene and its catalytic activity. This article provides an overview of the DB-interoperation problem, and offers several solutions. It discusses how links are used in molecular biology DBs, and describes the potential stumbling blocks when DB links are created and used.