Term
| enhanced entity-relationship (EER) model |
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Definition
| a model that has resulted from extending the original E-R model with new modeling constructs |
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Term
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Definition
| a subgrouping of the entities in an entity type that is meaningful to the organization and that shares common attributes or relationships distinct from other subgroupings |
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Term
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Definition
| a generic entity type that has a relationship with one or more subtypes |
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Term
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Definition
| change to higher level (supertype) filters to all lower levels (subtypes) automatically |
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Term
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Definition
| the process of defining a more general entity from a set of more specialized entity types |
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Term
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Definition
| the process of defining one or more subtypes of the supertype and forming super type/subtype relationships; each subtype is formed based on some distinguishing characteristic |
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Term
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Definition
| a type of constraint that addresses whether an instance of a super type must also be a member of at least one subtype |
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Term
| total specialization rule |
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Definition
| a rule that specifies that each entity instance of a super type must be a member of some subtype in the relationship |
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Term
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Definition
| a rule that specifies that an entity instance of a super type is allowed not to belong to any subtype; motorcycle example |
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Term
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Definition
| a constraint that addresses whether an instance of a super type may simultaneously be a member of two (or more) subtypes |
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Term
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Definition
| a rule that specifies that an instance of a super type may not simultaneously be a member of two (or more) subtypes (versus overlap rule) |
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Term
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Definition
| a rule that specifies that an instance of a super type may simultaneously be a member of two (or more) subtypes (versus disjoint rule) |
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Term
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Definition
| an attribute of a super type whose values determine the target subtype or subtypes |
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Term
| supertype/subtype hierarchy |
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Definition
| a hierarchical arrangement of super types and subtypes in which each subtype has only one supertype |
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Term
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Definition
| a set of one or more entity types and associated relationships grouped into a single abstract entity type |
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Term
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Definition
| a generic or template data model that can be reused as a starting point for a data modeling project |
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