Dynamic restructuring of databases with generation data structures

Abstract

Most logical database restructuring schemes require a complete pass through the database for reformatting. Our approach is to leave the database in situ and to permit a mixture (several generations) of structures to co-exist. Each generation of structure is described in a Generation Data Structure Schema, which has a generic structure of its own. A Restructuring Data Definition Language is proposed for describing the evolution from one schema to the next. Steps toward implementation are discussed.