Specifying reactive integrity control for active databases

Recent approaches to integrity enforcement in active databases suggest not only to check constraint violations by triggers but also to utilize triggers to perform inconsistency repair actions. However, for sophisticated reactions these approaches often require refinements of already derived integrity maintaining and inconsistency repairing triggers. We argue that analyzing and specifying reactions on constraint violations should exclusively be carried out in the conceptual design. We provide a declarative specification language for reactions on violations with an operational semantics, suitable to express most of the designers' intended behavior on constraint violations. We describe a design methodology for reaction specifications followed by a procedure to derive a set of stratified integrity enforcing triggers.<
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