chapter  11
12 Pages

Integrity constraints

We have seen in Chapter 4 that a deductive database can be divided into two parts, the EDB and the lOB. The EDB is the database of ground unit clauses, while the perfect model for the relations described by the predicates in a particular IDB is determined uniquely by the set of tuples comprising its associated EDB. We can therefore say that the perfect model is functionally dependent on the EDB.