An extended relational document retrieval model

摘要

Relational Data Base Management Systems offer a commercially available tool with which to build effective document retrieval systems. The full potential of the relational model for supporting the kind of ad hoc inquiry characteristic of document retrieval has only recently been explored. In addition, commercially available relational DBMS's also provide effective tools for managing document data bases by providing facilities for, inter alia, concurrency control, data migration and reorganization routines, authorization mechanisms, enforcement of integrity constraints, dynamic data definition, etc. This article will present a relational logical model to support a sophisticated document retrieval system in which flexible forms of inferential and associative searching can be performed. Examples of ad hoc inquiry will be presented in SQL. Several problems of particular importance to document retrieval will be discussed, including the importance of Conjunctive Normal Form in query formulation, unique aspects of document retrieval storage and processing overhead, and techniques for reducing the size of storage without severely impacting retrieval effectiveness.