A high level language implementation of the common features of data base definitions

Abstract

A high level language (GDBD - Generalized Data Base Definition) is presented for hierarchical relationships, network relationships, and data field definitions which, with a proper translator, can be used to generate data base definitions for any data base system with these features. The hierarchical relationships are specified by the production notation of formal languages. A notation for the "many-to-one" feature of network relationships has been specified which follows the hierarchical path of the "many", and points to the "one". The data field definitions as named by n-tuples where the name relates the data field to the hierarchical definition and positional parameters define the specific features of the data field. To test the GDBD language three test data bases have been designed. Hierarchical relationships and data field definitions for each of the three data bases are presented. Also two network relationships exist connecting the data bases. One of the test data bases has been used to demonstrate data base definitions for each of the following data base systems: ADAM, IDS, ISL-1, MARK IV, NMCS, SC-1, TDMS, UL/1, and a CODASYL type schema. This demonstrates the commonality of the three features of the GDBD language. A computer program has been designed and tested which translates a data base definition, presented in GDBD, into a metalanguage format. A second computer program must be written to translate the metalanguage into a data base definition for each data base system. Computer programs were written to translate the metalanguage into a data base definition for IBM's IMS and MRI's System 2000. The results of the translation of the three data bases for both data base systems are included. In this research the programs which translated the metalanguage assigned fixed values to the non-common features of data base definitions. Seven of the non-common features are described and a method of specifying these non-common features to the programs which translate the metalanguage is discussed.