CODASYL

Abstract: This report has been prepared by the Data Base Task Group which is an ad hoc committee of the CODASYL Programming Language Committee. The report details the recommendation of the Data Base Task Group to its parent committee. It consists of a proposal for a Data Description Language and a Data Manipulation Language. The Data Description Language is a language for describing a database. The Data Manipulation Language is language which, when associated with the facilities of a host language such as COBOL, PL/1, ALGOL, JOVIAL, FORTRAN..., allows manipulation of databases described by the Data Description Language. The specification of separate Data Description and Data Manipulation Languages is significant in that it allows databases described by the Data Description Language to be independent of the host languages used for processing the data. Of course, for this to be possible, the host language processors must be able to interface with such independent descriptions of data.

Abstract: It is the pleasure of the Conference on Data Systems Languages (CODASYL) to submit a second report of the Data Base Task Group (DBTG) for general distribution. This report reflects many of the changes, improvements and extensions suggested as a result of publication of the first report. It also reflects the request of the CODASYL Executive Committee that the specifications be separated into two categories, namely 1) those elements that would be necessary for an independent data description language and 2) those elements that would enable COBOL to interface properly with data described in that independent data description language. With this report as the base, CODASYL has now established a new standing committee, the Data Description Language Committee, independent of and equal to the Planning, Systems and Programming Language Committees. It is envisioned that from the base already established by the DBTG report this new committee will finalize the specifications for a common data description language, independent of but common to many other higher level programming languages. Simultaneously, the Programming Language Committee will develop COBOL extensions based on Section 4 (COBOL Sub-schema) and Section 5 (COBOL Data Manipulation Language). It is hoped that organizations responsible for other programming languages will develop the appropriate sub-schema and data manipulation language features for their language. While this report is not classified as a final CODASYL specification of a common language, it does represent many years of work and the best thinking of many recognized experts. Therefore we believe it is practical and appropriate for implementations to be made based on these specifications so that a foundation of experience may be established from which to further evolve and refine the specifications of a common data description language.

Abstract: This paper presents in tutorial fashion the concepts, notation, aud data-base languages that were defined by the CODASYL Data Description Language and Programming Language Committees. Data structure diagram notation is explained, and sample data-base definition is developed along with several sample programs. \" Advanced features of the languages are discussed, together with examples of their use. An extensive bibliography is included.