Terminological logics for schema design and query processing in OODBs

Knowledge Representation Meets Databases 1994

计算机科学;社会科学（总论）

D. Beneventano ; S. Bergamaschi ; S. Lodi ; C. Sartori

Others  :  http://CEUR-WS.org/Vol-1/beneventano-et-al-long.pdf
PID  :  17330

来源: CEUR

【 摘 要 】

The paper introduces ideas which make feasible and elective the application of Terminological Logic (TL) techniques for schema designand query optimization in Object Oriented Databases(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 frame work ofter minological reasoning. Complex object data models, recently proposed inthe area of OODBs, are more expressive than actually implemented TL languages in some aspects. For instance, most of the complex object data models introduce adistinction between objects withidentityandvalues,which is not present in TLlan-guages. Further,complex object models usually support additional type constructors, such asset andsequence. Mostimportantly, these models usually support therep-resentation and management of cyclic classes. These problems have found a solution in [Bergamaschi and Nebel,1992;1993] , bythe adoptionofanextended TL named ODL. A real database specificational ways include sasetof rules, the so-called integrity constraints , which should guarantee data consistency. Constraints are expressed invariousfashions, depending on the data model: e.g. subsets of first order logic,or inclusion dependencies and predicates on row values, or methods in OO environments. Inparticular OO methods are programs whose semantics cannot being spected by anautomatic reasoner. A first, necessary, improvementis to express atleast a class of integrity constraints at schema level. Our protaxonomic reasoning for the different tasks of schema design and query optimzation. Let us examine separately the two aspects of schema design and query optimization.