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. |
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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 property by which subtype entities inherit values of all attributes and instances of all relationships of their supertype. |
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Term
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Definition
| The process of defining a more general entity type from a set of more specialized entity types. |
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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
| The process of defining one or more subtypes of the supertype and forming supertype/subtype relationships. |
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Term
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Definition
| A type of constraint that address whether an instance of a supertype 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 each entity instances of supertype must be a member of some subtype in the relationship. |
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Term
| Partial specialization rule |
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Definition
| A rule that specifies that an entity instance of a supertype is allowed not to belong to any subtype. |
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Term
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Definition
| A constraint that addresses whether an instance of a supertype 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 supertype may not 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 supertype may simultaneously be a member of two (or more) subtypes. |
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Term
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Definition
| An attribute of a subtype whose values determine the target subtype or subtypes. |
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Term
| Supertype/subtype hierarchy |
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Definition
| A hierarchy arrangement of supertypes and subtypes in which each subtype has only one supertype. |
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Term
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Definition
| A generic or template data model that can be revised as a starting point for a data modeling project. |
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