Automatic database system conversion: schema revision, data translation, and source-to-source program transformation

Changing data requirements present database administrators with a difficult problem: the revision of the schema, the translation of the stored database, and the conversion of the numerous application programs. This paper describes an automatic database system conversion facility which provides one approach for coping with this problem. The Pure Definition Language and the Pure Manipulation Language have been designed to facilitate the conversions specified in the Pure Transformation Language. Two conversions and their effect on retrievals are demonstrated.