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Database Description with SDM: A Semantic Database Model

To solve the problems caused by the merger, no schema changes are required. Merge the customer entity sets removing duplicate tuples with the same social- security field. Before merging the branch entity sets, prepend the old bank name to the branch-name attributeineachtuple.The employee entity sets can bemerged directly, and so can the payment entity sets. No duplicate removal should be performed. Before merging the loan and account entity sets, whenever there is a number common in both the banks, the old number is replaced by a new unique number, in one of the banks | Database Description with SDM A Semantic Database Model MICHAEL HAMMER Massachusetts Institute of Technology and DENNIS McLEOD University of Southern California SDM is a high-level semantics-based database description and structuring formalism database model for databases. This database model is designed to capture more of the meaning of an application envứonment than is possible with contemporary database models. An SDM specification describes a database in terms of the kinds of entities that exist in the application envừonment the classifications and groupings of those entities and the structural interconnections among them. SDM provides a collection of high-level modeling primitives to capture the semantics of an application envứonment. By accommodating derived information in a database structural specification SDM allows the same information to be viewed in several ways this makes it possible to dứectly accommodate the variety of needs and processing requứements typically present in database applications. The design of the present SDM is based on our experience in using a preliminary version of it. SDM is designed to enhance the effectiveness and usability of database systems. An SDM database description can serve as a formal specification and documentation tool for a database it can provide a basis for supporting a variety of powerful user interface facilities it can serve as a conceptual database model in the database design process and it can be used as the database model for a new kind of database management system. Key Words and Phrases database management database models database semantics database definition database modeling logical database design CR Categories 3.73 3.74 4.33 1. INTRODUCTION Every database is a model of some real world system. At all times the contents of a database are intended to represent a snapshot of the state of an application environment and each change to the database should reflect an event or sequence of events occurring in .