CODEWITHSUNDEEP
databasedatabase-design
Ris
Ris

Reputation: 1912

one or more phone numbers for every user

I am making a user entity here, there are some things that are not clear to me. So I have an attribute phoneNo that user may have one or more phone numbers , so if I need something like that do I make a new entity phoneNumber and have a phoneNo as PK ? Also similar thing with customers where customer can either be regular or premium , do I have to make a new entity CustomerType ? I didnt want to make a new entity for isAdmin because it can be either off or on ? would this be ok...

this is what I am talking about

enter image description here

Upvotes: 2

Views: 133

Answers (1)

Bill Karwin
Bill Karwin

Reputation: 562368

If a given attribute may have multiple values, use a separate table. Your isAdmin attribute probably can have only one scalar value, which may be true or false.

I would expect the reference in that diagram to go the other way. That is, User may have multiple phoneNumbers, so you should make phoneNumber reference User. And then you would not need a column phoneNo in the User table.

The diagram you have shows the opposite relationship, in which a phoneNumber could have multiple Users.

The direction of the reference for CustomerType is consistent with what I would expect it to be. That is, there may be multiple Users with a given CustomerType.

Upvotes: 2

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