Extending the data base relational model to capture more meaning

During the last three or four years several investigators have been exploring 'semantic models' for formatted data bases. The intent is to capture (in a more or less formal way) more of the meaning of the data, so that data base design can become more systematic and the data base system itself can behave more intelligently. Two major thrusts are clear:1) the search for meaningful units that are as small as possible --- atomic semantics2) the search for meaningful units that are larger than the usual n-ary relation --- molecular semantics.In this paper we propose extensions to the relational model to support certain atomic and molecular semantics. These extensions represent a synthesis of many ideas from the published work in semantic modeling.