bddbddb stands for BDD-Based Deductive DataBase. It is an implementation of Datalog, a declarative programming language similar to Prolog for talking about relations. What makes bddbddb unique is that it represents the relations using binary decision diagrams (BDDs). BDDs are a data structure that can efficiently represent large relations and provide efficient set operations. This allows bddbddb to efficient represent and operate on extremely large relations – relations that are too large to represent explicitly.