Flashcards
Enhanced Entity Relationship Diagram
Cards in this deck (17)
- 1A generic entity type that has a relationship with one or more subtypesSupertype
- 2An entity type that includes one or more distinct subgroups which require to be represented in a data model.Supertype
- 3A subgrouping of the entities in an entity type that has attributes distinct from those in other subgroupingsSubtype
- 4̈ Subtype entities inherit values of all attributes of the supertypeAttribute Inheritance
- 5An instance of a subtype is also an instance of the supertypeAttribute Inheritance
- 6The process of defining a more general entity type from a set of more specialized entity types. BOTTOM- UPGeneralization
- 7The process of defining one or more subtypes of the supertype and forming supertype/subtype relationships. TOP-DOWNSpecialization
- 8Whether an instance of a supertype must also be a member of at least one subtypeCompleteness Constraints
- 9̈Total Specialization Rule: Yes(double line)
- 10̈Partial Specialization Rule: No(single line)
- 11Whether an instance of a supertype may simultaneously be a member of two (or more) subtypesDisjointness Constraints
- 12An instance of the supertype can be only ONE of the subtypes̈Disjoint Rule:
- 13An instance of the supertype could be more than one of the subtypes̈Overlap Rule
- 14An attribute of the supertype whose values determine the target subtype(s)Subtype Discriminator
- 15– a simple attribute with alternative values to indicate the possible subtypesDisjoint
- 16– a composite attribute whose subparts pertain to different subtypes. Each subpart contains a Boolean value to indicate whether or not the instance belongs to the associated subtypeOverlapping
- 17Set of one or more entity types and associated relationships grouped into a single abstract entity typeEntity Clusters
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- 1 Information Management Flashcards on Enhanced Entity Relationship Diagram, created by Shiro Midori on 03/12/2021.
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- Shiro Midori
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