Ch03_Summary - INFS 428 Chapter 3 Summary – Data Modeling...

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Unformatted text preview: INFS 428 Chapter 3 Summary – Data Modeling Extended ERD Attribute inheritance – a property by which subtype entities inherit values of all attributes and instances of all relationships of their supertype Completeness constraint- A type of constraint that addresses the question whether an instance of a supertype must also be a member of at least one subtype. The completeness constraint has two possible rules: total specialization and partial specialization Disjoint rule- Specifies that if an entity instance (of the supertype) is a member of one subtype, it cannot simultaneously be a member of two (or more) subtypes Disjointness constraint – a constraint that addresses whether an instance of a supertype may simultaneously be a member of two or more subtypes Enhanced entity-relationship (EER) model- The model that has resulted from extending the original E-R model with new modeling constructs such as supertypes and subtypes Entity cluster- A set of one or more entity types and associated relationships grouped into a single abstract...
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This note was uploaded on 02/20/2012 for the course ACC 3101 taught by Professor Tom during the Spring '11 term at American University in Bulgaria.

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Ch03_Summary - INFS 428 Chapter 3 Summary – Data Modeling...

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