FORMULATING GLOBAL INTEGRITY CONSTRAINTS DURING DERIVATION OF GLOBAL SCHEMA

In a heterogeneous distributed database environment, each component da tabase is characterized by its own logical schema and its own set of i ntegrity constraints. The task of generating a global schema from a co nstituent local schemata has been addressed by many researchers. The c omplementary problem of using multiple sets of integrity constraints t o create a new set of global integrity constraints is examined in this paper. These global integrity constraints facilitate both query optim ization and update validation tasks.