Terminological Logics for Schema Design and Query Processing in OODBs

Applying taxonomic reasoning and TL in database environment for traditional semantic data models led to a number of promising results for database schema design and other relevant topics, as query processing and data recognition. In particular, in [ Bergamaschi and Sartori,1992 ] a general theoretical framework has been presented, which supports conceptual schema acquisition and organization by preserving coherence and minimality w.r.t. inheritance, exploiting the framework of terminological reasoning. Complex object data models, recently proposed in the area of OODBs, are more expressive than actually implemented TL languages in some aspects. For instance, most of the complex object data models introduce a distinction between objects with identity and values, which is not present in TL languages. Further, complex object models usually support additional type constructors, such as set and sequence. Most importantly, these models usually support the representation and management of cyclic classes. These problems have found a solution in [ Bergamaschi and Nebel,1992; 1993 ] , by the adoption of an extended TL, named ODL.