Questions tagged [entity]
The entity tag has no usage guidance.
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May a weak entity have relation to another weak entity which is already related with a strong entity?
Imagine there is a weak entity B which depends on a strong entity A, and another weak entity C that depends on the weak entity B.
How would we select the PK s for the entity C in such a case ?
To be ...
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How can I transform an exclusive constraint relationship from ER to RM model?
Let say we have two entities TEACHER and COURSE. There are two relationships between them. A TEACHER can teaches a COURSE, and also can learn a COURSE, however, the TEACHER cannot teach and learn a ...
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Is it good to join on different tables depending on discrimination column?
I want to build a MySQL database with different trading card, all belonging to different games. Each card, depending on the game, has several properties. For example :
A Magic: The Gathering card has ...
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