root/logseq_notes
1
0
Fork 0
Code Issues Pull requests Actions Packages Projects Releases Wiki Activity

Auto saved by Logseq

Browse source
This commit is contained in:
Ryan 2023-06-14 14:35:28 +08:00
parent 03c1569ca7
commit f355978385
1 changed files with 9 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
pages/总复习2023t1.md
View file

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