CODEWITHSUNDEEP
umlclass-diagram
AIR
AIR

Reputation: 73

Class Diagram , composition relationship

I have three classes:

-User class

-Role class

-UserRole class : to join both classes

Each user can have multiple roles.

So, I made this class diagram:

Class Diagram

Is the composition relationship between classes and the cardinalities correct?

Upvotes: 0

Views: 134

Answers (2)

qwerty_so
qwerty_so

Reputation: 36295

You can safely omit the composition diamonds as they add no real semantic to the model. Compositions are used on a metaphoric level and are more food for philosophers than anyone else.

Now for the multiplicities. A UserRole binds exactly one user to one role. You can have multiple UserRoles to reflect different roles for single or multiple users. So you should place a 1 to the left and right multiplicities.

Upvotes: 1

Jim L.
Jim L.

Reputation: 6529

No. When the relationship goes away, you don't want the other things to get deleted. The pointy ends must also be 1's.

Upvotes: 1

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