Document Type

Other

Publication Date

7-1998

Abstract

With rapid progress in application development and technologies there is an increasing need to specify and handle complex schema changes of databases The existing support for schema evolution in current OODB systems is limited to a pre-defined taxonomy of simple schema evolution operations with fixed seman- tics We have proposed an extensible framework SERF(Schema Evolution using an Extensible Re-Usable Framework) for schema transformations to address this open problem The SERF framework succeeds in giving the user the flexibility to define the semantics of their choice the extensibility of defining new complex transformations and the power of re-using these transformations through the notion of templates In this paper we now report on OQL-SERF the realization of our concepts based on the ODMG standard on top of PSE (Persistent Storage Engine) Object Design Inc We have utilized not only the ODMG object model but have also used OQL as the database transformation language the ODMG MetaData Repository for providing meta information utilized by the templates and Java s binding of ODL In order to design a schema evolver manager for ODMG we had to develop a taxonomy of schema evolution primitives for the ODMG object model that is minimally complete Related to the implementation of OQL-SERF on top of PSE (Persistent Storage Engine) we also describe the design and implementation issues involved in developing a java-based schema evolution manager as well as an OQL query engine for PSE Our working prototype OQL-SERF demonstrates the capability of our SERF approach to handle a large set of schema transformations

DOI

WPI-CS-TR-98-14

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