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Structured Development for Real-Time Systems by Stephen J. Mellor, Paul T. Ward

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Chapter 10. Modeling Stored Data

Introduction

The data schema models a system as a passive entity — as a network of categories that are linked to one another by their associations. In this chapter, we will introduce the notation for the data schema, give some illustrations of how the schema can be used, and introduce rules for judging whether a data schema is internally consistent and whether it communicates clearly. The data schema uses the basic notation and concepts of the entity-relationship diagram introduced by Chen [1], with some extensions to the notation and some refinement rules proposed by Flavin [2]. We believe that the model described in this chapter substantially meets the criteria for an adequate semantic data model proposed by Schrefl, ...

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