Design and implementation of an extendible integrity subsystem

Tnls paper presents a powerful integrrty subsystem, which is implemented in the SABRE database system. The specification language is simple. Tne enforcement algorithm is general, in particular, it handles referential dependency and temporal assertions. Specialized strategies efficiently treat each class of assertions. The system automatically manages integrity checkpoints. Also, an efficient method is described for processing assertions involving aggregates. An analysis exhibits the value of the algorithms. It 1s shown that, in general, this method is better than the query modification method for domain assertions. Measures have also been done for giving the cost added for controlling integrity in comparison with the cost of the request itself.