A Normal Form For Entity-Relationship Diagrams
نویسنده
چکیده
In this paw=, a normal form for entity-relationship diagrams and the objectives for such a normal form are presented. A normal form entity-relationship diagram may consist of composite attributes, multivalued attributes, and special types of relationship sets such as existence dependent, identifier dependent, ISA, UNION, INTERSECT, and DECOMPOSE relationships. A comprehensive algorithm is given to translate a normal form entity-relationship diagram to a set of relations. We show that all relations generated are either in third normal form or fifth normal form. General guidelines and detailed steps for converting an entity-relationship diagram to a normal form entity-relationship diagram are presented. These steps can also be used as guidelines for designing databases using entity-relationship approach.
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