All Questions
Tagged with erd constraint
3 questions
0
votes
1
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Covering and overlapping constraints
Given that there are 15 entities in E1, 20 entities in E2 and 25 entities in E3, what's the maximum and the minimum number of entities in E0? It's also known that the ISA hierarchy follows the ...
- 111
1
vote
1
answer
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Clarification on Cardinality and Participation
I'm currently redesigning a schema with 20 or so tables and my first task is to create an ERD from the existing tables/constraints/relationships. This has proven more difficult than I expected because ...
- 121
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1
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How to enforce a constraint over multiple tables?
I have the following five tables:
PRODUCT
FEATURE
PROVIDER
PROVIDER_PRODUCT
PROVIDER_FEATURE
The logic is as follows:
A generic PRODUCT can have one or more FEATUREs. There are different ...
- 235