Global semantic integrity constraints ensure the integrity and consistency of data spanning distributed databases. In this chapter, we discuss a novel representation technique for expressing semantic integrity constraints for XML databases. We also provide the details of XConstraint Checker, a general framework for checking global semantic constraints for XML databases. The framework is augmented with an efficient algorithm for checking these global XML constraints. The algorithm is efficient for three reasons: 1) the algorithm does not require the update statement to be executed before the constraint check is carried out; hence, we avoid any potential problems associated with rollbacks, 2) sub constraint checks are executed in parallel, and 3) most of the processing of algorithm could happen at compile time; hence, we save time spent at run-time. As a proof of concept, we present a prototype of the system implementing the ideas discussed in this paper.
Integrity constraint checking in stratified databases
