Correctness of semantic integrity checking in database management systems
Although today's applications are very demanding with regard to semantic integrity, few database systems provide capabilities of this type. In this paper, a definition of integrity constraint is given in terms of relational algebra and certain aspects are then discussed concerning transaction management in the presence of such integrity constraints. In particular, the problem of when to enforce a set of integrity constraints during the execution of a transaction is addressed. For this purpose the notion of integrity enforcement schedule is introduced. An integrity enforcement schedule represents the sequence of integrity checking actions performed during the execution of a transaction. A correctness criterion for the integrity enforcement schedules is established, and a sufficient condition for the correctness is provided. Finally the notion of minimal integrity enforcement schedule is introduced. The minimal integrity enforcement schedules are those integrity enforcement schedules in which every constraint is verified ``as soon as possible''. For this reason they are really desirable in the transaction management to avoid expensive rollingback operations. Algorithms for their construction are presented, together with the associated correctness proofs.
scientific article; zbMATH DE number 4033147