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Ryan 2023-06-14 14:35:28 +08:00
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@ -962,14 +962,17 @@
- Most useful additional concept of EER model: - Most useful additional concept of EER model:
specialization/generalization. specialization/generalization.
- Superclass :-> An entity type that includes one or more distinct - Superclass :-> An entity type that includes one or more distinct
id:: 64895f2f-b868-46ec-9d80-7079eaf3197d
subgroupings of its occurrences. subgroupings of its occurrences.
- Superclass/subclass relationship is one-to-one - Superclass/subclass relationship is {{c1 one-to-one
(1:1). id:: 64895f70-57e0-4023-9c32-34f1380aba1e
(1:1).}} #flashcard
- Superclass may contain overlapping or distinct - Superclass may contain overlapping or distinct
subclasses. subclasses.
• Not all members of a superclass need be a - Not all members of a superclass need be a
member of a subclass. member of a subclass.
- Subclass :-> A distinct subgrouping of occurrences of an entity - Subclass :-> A distinct subgrouping of occurrences of an entity
id:: 64895f39-d886-436b-9afe-ba75d37c8b45
type. type.
- LATER designing ER diagram - LATER designing ER diagram
- DONE Block 3 - DONE Block 3