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Ryan 2023-06-14 15:12:30 +08:00
parent 3f993adc01
commit 18a9d2a0be
3 changed files with 1231 additions and 1209 deletions

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@ -973,6 +973,7 @@
id:: 64896085-645b-408f-b17a-109b6cd82aeb
specialization/generalization:
- participation constraints :-> Determines whether every member in superclass
id:: 6489683b-319a-4173-a55b-6fa3b2c09aeb
must participate as a member of a subclass.
- May be mandatory or optional. #flashcard
id:: 648960d0-ae7f-4452-a1b9-cab8a9b13443
@ -980,10 +981,8 @@
member of subclass
- Optional: member of superclass may be member
of subclass.
- disjoint constraints :-> Describes relationship between members of the
subclasses and indicates whether member of a
superclass can be a member of one, or more than
one, subclass. #flashcard
- disjoint constraints :-> Describes relationship between members of the subclasses and indicates whether member of a superclass can be a member of one, or more than one, subclass. #flashcard
id:: 6489683b-039f-4161-94b1-91177f713ee5
- Disjoint: member of superclass is member of at
most one subclass
- Disjoint: member of superclass is member of at
@ -1002,12 +1001,10 @@
- Subclass :-> A distinct subgrouping of occurrences of an entity
id:: 64895f39-d886-436b-9afe-ba75d37c8b45
type.
- When to use them? eith
1. There are attributes that apply to some (but
not all) instances of an entity.
2. The instances of a potential subclass
participate in a relationship unique to that
subclass.
- When to use them? either one or both #flashcard
id:: 6489683b-7d47-4246-afdf-83fdb35a00f6
- There are attributes that apply to some (but not all) instances of an entity.
- The instances of a potential subclass participate in a relationship unique to that subclass.
- LATER designing ER diagram
- DONE Block 3
collapsed:: true