Integrity Constraint Reformulation for Efficient Validation

Constraint validation has bcc?n difficult to implement efficiently. The major reason for this difficulty lies in the state-dependent nature of integrity constraints and the rt~quiremcnt of both high-level spc&fication and cfficirnt runtimc cnforccmcnt. In this paper, we propose a constraint reformulation approach to rfficicnt constraint validation. We also demonstrate how this knowledge-basrd constraint rcfornmlation can be naturally accomplished in the gcncral framework of problem reformulation with the technique of antecedent derivation. We formalize thr reformulation of an integrity constraint as a tree-starch process where the search space is thtr set of all semantic-equivalent alternatives of the original constraint. We also develop control strategies and mcta-level rules for carrying out the search c?fficicntly. The major contribution of this work is a new promising approach to cfficirnt constraint validatiun and a general framework to accomplish it.