Splitting the conceptual schema
William Kent · Very Large Data Bases · 1980
The conceptual schema at the heart of the ANSI DBSG three-schema framework has been the subject of several polarizing arguments. Splitting the concep-tual schema yields a four-schema framework which resolves some of those arguments. The proposed approach also provides a natural growth path for the evolution of current data base systems, with gradual integration of dictionary and database design facilities.