Virtual schemas and bases
We have informally presented the functionality of a view mechanism for object-oriented databases. The approach is intended to favor the dynamic nature of intensional and extensional data by allowing it to be easily and intensively explored.
A virtual schema defines a context on which application programs can operate. Its activation, which results in the creation of a virtual base, represents a context switch and provides a means for dealing with the dynamics of database applications which is not favored by conventional object-oriented models.
There are yet several issues not yet fully resolved such as the placement of virtual classes in the hierarchy, strategies for solving resolution conflicts, or the lazy evaluation of virtual and imaginary extensions. Furthermore, it is necessary to explore how the view mechanism can be used in several contexts such as schema updates, object versionning, integrity constraint verification, and active databases. In particular, the use of deductive capabilities in conjunction with a view mechanism seems to be a promissing approach which remains to be studied.
KeywordsVirtual Object Class Extension Object Identifier Real Schema View Mechanism
Unable to display preview. Download preview PDF.
- 1.S. Abiteboul and A. Bonner. Objects and Views. In Proc. ACM SIGMOD Conference on Management of Data, pages 238–247, 1991.Google Scholar
- 2.F. Bancilhon, C. Delobel, and P. Kannelakis. Building an Object-Oriented Database System — The Story of O 2. Morgan Kaufmann, 1992.Google Scholar
- 3.Elisa Bertino. A View Mechanism for Object-Oriented Databases. In International Conference on Extending Data Base Technology, pages 136–151, Vienna, March 1991.Google Scholar
- 4.Alexander Borgida. Modeling Class Hierarchies with Contradictions. Technical report, Rutgers University, New Brunswick (NJ US), 1988.Google Scholar
- 5.W. Gotthard, P. C. Lockermann, and A. Neufeld. System-Guided View Integration for Object-Oriented Databases. IEEE Transaction on Knowledge and Data Engineering, 4(1), Feb. 1991.Google Scholar
- 6.Stephen Hayne and Sudha Ram. Multi-user view integration system (muvis): An expert system for view integration. IEEE Data Engineering, pages 402–409, July 1990.Google Scholar
- 7.S. Heiler and S.B. Zdonik. Object Views: Extending the Vision. In IEEE Data Engineering Conference, pages 86–93, Los Angeles, 1990.Google Scholar
- 8.M. Kaul, K. Drosten, and E.J. Neuhold. ViewSystem: Integrating Heterogeneous Information Bases by Object-Oriented Views. IEEE Data Engineering, pages 2–10, July 1990.Google Scholar
- 9.Henry Lieberman. Using Prototypical Objects to Implement Shared Behavior in Object-Oriented Systems. In Proc. OOPSLA, Portland, OR, 1986.Google Scholar
- 10.Guido Moerkotte and Andreas Zachmann. Multiple Substitutability without Affecting the Taxonomy. In International Conference on Extending Data Base Technology, 1992.Google Scholar
- 11.Amihai Motro. Superviews: Virtual Integration of Multiple Databases. IEEE Transactions on Software Engineering, 13(7):785–798, July 1987.Google Scholar
- 12.ANSI/X3/SPARC Study Group on Database Management Systems. Interim report. A CM SIGMOD Bulletin 7,N2, 1975.Google Scholar
- 13.Joel Richardson and Peter Schwarz. Aspects: Extending Objects to Support Multiple, Independent Roles. In Proc. ACM SIGMOD Conference on Management of Data, pages 298–307, 1991.Google Scholar
- 14.Elke Rundensteiner. A Class Integration Algorithm and Its Application for Supporting Consistent Object Views. Technical Report 92-50, Department of Information and Computer Science, University of Califoria, Irvine, May 1992.Google Scholar
- 15.Elke Rundensteiner and Lubomir Bic. Automatic View Schema Generation in Object-Oriented Databases. Technical Report 92-15, Department of Information and Computer Science, University of Califoria, Irvine, Jan. 1992.Google Scholar
- 16.M. H. Scholl, Christian Laasch, and Markus Tresch. Updatable Views in Object-Oriented Databases. In Proc. DOOD, Munich, Germany, 1991.Google Scholar
- 17.Michael Schrefl and Erich J. Neuhold. Object Class Definition by Generalization Using Upward Inheritance. In Proc. IEEE Data Engineering Conf., pages 4–13, Los Angeles, Feb. 1988.Google Scholar
- 18.John J. Shilling and Peter F. Sweeney. Three Steps to Views: Extending the Object-Oriented Paradigm. In Proc. OOPSLA, New Orleans, Louisiana, 1989.Google Scholar
- 19.Katsumi Tanaka, Masatoshi Yoshikawa, and Kozo Ishihara. Schema Virtualization in Object-Oriented Databases. In Proc. IEEE Data Engineering Conf., pages 23–30, Los Angeles, Feb. 1988.Google Scholar
- 20.Kazuyuki Tsuda, Kensaku Yamamoto, Masahito Hirakawa, Minoru Tanaka, and Tadao Ichikawa. MORE: An Object-Oriented Data Model with Facility for Changing Object Structures. IEEE Transactions on Knowledge and Data Engineering, 3(4):444–460, Dec. 1991.Google Scholar