Constraint & Test Verification in Parallel Database Systems

Maintenance of integrity is an important issue in parallel database systems. Testing the validity of a large number of constraints against large databases and after each update operation is an expensive process. Many different methods for integrity constraint maintenance have been proposed by researchers. The main focus of the methods in the literature is the simplification process. The simplified forms of the integrity constraints (Cs) are called the integrity tests. The integrity constraints defined on the database must be semantically consistent and there is no contradiction among them. Adding a new constraint(s) may contradict with other existing integrity constraints in the database. This article concentrates on how to verify if a new integrity constraint contradicts with the existing constraint set defined on the parallel databases. Another interest of this article is the way of the system checks whether or not the constraints have been invalidated by a transaction and repair the integrity violations if there are violations.