Questions tagged [entity]
The entity tag has no usage guidance.
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 ...
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 ...
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 ...