Abstract
A DBMS user view consists of a Data Definition Language (DDL) which defines the data model and a Data Manipulation Language (DML) which defines the access scheme for that data model. To permit different user views to share a common data base, it is necessary to establish a single physical representation for the data base. The physical representation must be compatible with the data model of each logical view involved. This can be accomplished by mapping the DDL commands of each logical view into a set of Model Definition Primitive (MDP) commands which describe the physical representation of that logical view. The MDP descriptions of each physical representation can then be merged into one MDP description. The existence of Model Definition primitives has already been established (Dl); therefore, the purpose of this paper is twofold:1. Describe a DDL compiler for each view whose MDP output can be easily merged.2. Define the rules under which a merging program operates.In this paper we do not discuss the effects of the above merging concept on implementation of any DML.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
