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I am studying this ERD:
The bank and the customer are obviously strong entities because they are a bank and a person.The bank branch is clearly a weak entity because it depends on the bank assosciated with it.How is a account and a loan not weak entities?Since a loan and a account depend on the customer and the bank branch.How am I thinking wrongly of this?
A weak entity type is an entity type identified by some attribute/s together some related object (https://en.m.wikipedia.org/wiki/Weak_entity)
For instance, the room of a hotel might be seen as a weak entity type since it is identified by the hotel, and a number. A number itself cannot identify a room because there are several rooms with the same number (in different hotels).
In your exercise, it seems that loans and accounts have their own unique identifier number. That is, there are no two loans (or accounts) with the same loanNo (accountNo), not even in different banks. Hence, in this exercise, loans and accounts can be seen as strong entities.
