抄録
Recently efforts have been directed toward implementing more comprehensive relationl database system. Most of them are the type of database management suited to document retrieval system used in bussiness application, but also they are potentially suited to a document retrieval system.
This paper first points out the advantages of relational database system to handle bibliographic data in document retrieval system.
Secondly, it classifies the query languages which have been developed for relationl database system and examines their features and concepts from a user's point of view.
Thirdly, it shows how SEQUEL (a mapping-oriented language) can be used to express retrieval
operations of bibliographic data.
Fourthly, it discusses the use of natural language as a query language.
It concludes with remarks about some development of database computer.
