Further Improvements on Integrity Constraint Checking for Stratifiable Deductive Databases
Sin Yeung Lee, Tok Wang Ling · Very Large Data Bases · 1996
Integrity constraint checking for stratifiable deductive databases has been studied by many authors. However, most of these methods may perform unnecessary checking if the update is irrelevant to the constraints. [Lee94] proposed a set called relevant set which can be incorporated in these works to reduce unnecessary checking. [Lee94] adopts a top-down approach and makes use of constants and evaluable functions in the constraints and deductive rules to reduce the search space. In this paper, we further extend this idea to make use of relational predicates, instead of only constants and evaluable functions in [Lee94]. We first show that this extension is not a trivial one as extra database retrieval cost is incurred. We then present a new method to construct a pre-test which can be incorporated in most existing methods to reduce the average checking costs in terms of database accesses by a significant factor. Our method also differs from other partial checking methods as we can handle multiple updates.