CS 545 - Database Research Seminar, Spring 96/97

Transforming Databases with Recursive data Structures.

Anthony Kosky

Information and Computing Sciences Division
Lawrence Berkeley National Laboratory, Berkeley, CA 94720
EMail: Anthony_Kosky@lbl.gov


The need to transform data between heterogeneous databases arises from a number of critical tasks in data management, including database integration, schema evolution and the maintenence of multiple user views. These tasks are complicated by schema evolution in the underlying databases, and by the presence of non-standard database constraints.

In this talk I will argue that existing techniques are not adequate to deal with tranformations involving semantic or object-oriented data models, and, in particular that there is a need to take account of the interactions between database transformations and constraints, and to allow for partial specifications of complex data objects.

I will describe a declarative language, _WOL_, based on Horn-clause logic, for specifying database transformations and constraints, and its implementation in a system called _Morphase_. The implementation takes transformations specifications in WOL and manipulates their clauses into a normal form which can then be translated into an underlying database programming language.

This work was done as part of a PhD thesis at the University of Pennsylvania, with advisors Susan Davidson and Peter Buneman.