Automating Relational Database Support for Objects Defined by Context-Free Grammars - the Intension-Extension Framework.

Abstract

We are designing a framework that provides a common foundation for the integration of databases with other areas of computer science and engineering. This framework is based on the fundamental concepts: context-free grammars and database relations.Our goal is to provide automatic database support for complex objects that can be described by context-free grammars. Such support should include Data Definition, Data Update, Grammar Catalog Generation, Data Retrieval, and Database Restructuring. This paper addresses the first three areas: Data Definition: GeneRel automatically generates a set of normalized relational schemes under which ob,iects derived from a given grammar can be stored. Data Update: GenParse automatically generates parser specifications with insertion statements for storing sentences acceptable by a given grammar. Grammar Catalog Generation: GenRel, when applied to a meta-grammar, generates relations in which grammars derived from the meta-grammar can be stored. Furthermore, GenRel and GenParse can be implemented through the specification of semantic actions in a compiler-compiler specification of the meta-grammar. We believe that GenRel and GeneParse, together with our related efforts towards providing support for data retrieval and database restructuring in this environment, provide a tool that eliminates the need for manual relational database design, enhances data storage and querying, aids in the process of database restructuring, and provides a common foundation for the integration of databases with other areas of computer science and engineenng.