Some Generic Correspondences to Define Object Databases on Top of Relational Databases

Introduction As researchers in Artiøcial Intelligence, our ørst aim was to allow our expert system shell Smeci [Sme90] the access to relational databases during reasoning. We also needed to save in a database complex objects that seemed interesting for further utilization, in particular the knowledge bases and the results of reasoning. To this end, we have deøned generic correspondences [Leb93] between relational concepts and some of the object concepts that are common to most object models. These correspondences allow to translate relational data into complex objects and conversely. They generalize the mapping proposals that we found in the literature [Lee90, WBL+91, KJA93]. An implementation of these deønitions has been realized. This is the Driver system [Leb92] whose speciøcity is to deøne an object oriented dbms (oodbms) on a relational dbms (rdbms). In Driver