Integrity constraints are rules which should guarantee the integrity of a database. Provided that an adequate mechanism to express them is available, the following question arises: is there any way to populate a database which satisfies the constraints supplied by a designer? Constraints are expressed in various fashions, depending on the data model: in logic environment they are usually some subset of ifrst order logic formulas, SQL2 allows general forms of inclusion dependencies and predicates to be evaluated on row values, while in OODBMSs most of the stuf is often left to the writing of methods. The contribution of the present work is twofold: first, to extend the expressiveness of complex object data models to capture the semantics of a relevant set of state constraints; second, to provide a specialized reasoner based on the tableaux calculus which is able to check the coherence of an object database schema with constraints.
typing constraints and integrity rules. In order to improve the expressiveness and maintain the decidability of the reasoning activities, we extended the kernel formalism into two alternative directions. The first formalism, ℒ, introduces the capability of expressing path relations. Because cyclic schemas are extremely useful, we introduce a second formalism, ℒ, with the capability of expressing cyclic descriptions but disallowing the expression of path relations. In fact, we showed that the reasoning activity in ℒ (i.e., ℒ with cycles) is undecidable.
We also demonstrated how techniques based on Description Logics are highly valuable in
another crucial activity of a DBMS: query optimization; the related work "Description logics for
semantic query optimization in object-oriented database systems" has been published on the
ACM Transactions on Database Systems [