Definition of External Schemas in ODMG Databases

ODMG 3.0 (January 2000) does not specify how to define external schemas in object oriented databases and only offers a very basic mechanism for defining views, called named queries. In this paper, a system and a language for defining external schemas in ODMG databases are presented. Both are based on a mechanism that avoids the generation of classes that are not necessary in external schemas. The proposed language is an extension of ODMG ODL and allows the definition of external schemas using the ODMG named queries for defining derived classes. Nevertheless, the proposed language is independent of the derived classes definition mechanism used.

[1]  Serge Abiteboul,et al.  Virtual Schemas and Bases , 1994, EDBT.

[2]  Johann Eder,et al.  Adding View Support to Odmg-93 1 , 1994 .

[3]  R. G. G. Cattell,et al.  The Object Database Standard: ODMG-93 , 1993 .

[4]  Renate Motschnig.  Requirements and Comparison of View Mechanisms for Object-Oriented Databases , 1996, Inf. Syst..

[5]  Cassio Souza dos Santos.  Design and Implementation of Object-Oriented Views , 1995, DEXA.

[6]  Elisa Bertino,et al.  A formal model of views for object-oriented database systems , 1997 .

[7]  Elisa Bertino,et al.  A View Mechanism for Object-Oriented Databases , 1992, EDBT.

[8]  José Samos,et al.  External Schema Generation Algorithms for Object Oriented Databases , 1996, OOIS.

[9]  Elisa Bertino,et al.  A Formal View of Object-Oriented Database Systems , 1997, Theory Pract. Object Syst..

[10]  Markus Tresch,et al.  Updatable Views in Object-Oriented Databases , 1991, DOOD.

[11]  Won Kim,et al.  On View Support in Object-Oriented Databases Systems , 1995, Modern Database Systems.

[12]  Johann Eder,et al.  Adding View Support to ODMG-93 (Invited Paper) , 1994, ADBIS.

[13]  Elke A. Rundensteiner.  Multiview: A Methodology for Supporting Multiple Views in Object-Oriented Databases , 1992, VLDB.

[14]  José Samos.  Definition of External Schemas in Object Oriented Databases , 1995, OOIS.

[15]  Francisco Araque,et al.  Sistema cooperativo para la integración de fuentes heterogéneas de información y almacenes de datos , 1999 .

[16]  Elke A. Rundensteiner,et al.  Automatic view schema generation in object-oriented databases , 1992 .

[17]  David J. DeWitt,et al.  The Object-Oriented Database System Manifesto , 1994, Building an Object-Oriented Database System, The Story of O2.