Using Temporary Integrity Constraints toOptimize

Integrity constraints are usually assumed to be permanent properties that must be satissed by any database state. However, there are many situations requiring also temporary constraints, that is, constraints that must hold only for a single database state. In this paper we propose a schema to deene both permanent and temporary constraints, that supports eecient constraint checking and semantic query optimization. The proposed schema associates integrity constraints to rules and queries, and it uses methods, that were originally deened for permanent constraints only, to perform constraint checking and semantic query optimization .