A formal representation of a property that a database is required to satisfy at any time in order to faithfully describe the real world represented by the database.
Published in Chapter:
Improving Constraints Checking in Distributed Databases with Complete, Sufficient, and Support Tests
Ali Amer Alwan (Universiti Putra Malaysia, Malaysia), Hamidah Ibrahim (Universiti Putra Malaysia, Malaysia), and Nur Izura Udzir (Universiti Putra Malaysia, Malaysia)
Copyright: © 2009
|Pages: 13
DOI: 10.4018/978-1-60566-242-8.ch037
Abstract
A database state is said to be consistent if and only if it satisfies the set of integrity constraints. A database state may change into a new state when it is updated either by a single update operation (insert, delete, or modify) or by a sequence of updates (transaction). If a constraint is false in the new state, the new state is inconsistent, therefore the enforcement mechanism can either perform compensatory actions to produce a new consistent state, or restore the initial state by undoing the update operation. The steps generate integrity tests that are queries composed from the integrity constraints and the update operations, and run these queries against the database, which check whether all the integrity constraints of the database are satisfied; are referred to as integrity checking (Alwan, Ibrahim, & Udzir, 2007; Ibrahim, 2006; Ibrahim, Gray & Fiddian, 2001), is the main focus of this chapter.