CODEWITHSUNDEEP
sqldb2check-constraints
pixel
pixel

Reputation: 10577

SQL Constraint to Enforce Rule

if I have tables like this:

GROUP(**GID**, DESC) -- GID IS PK    
USER(**UID**, FIRST, LAST, GID) -- UID IS PK, GID IS FK

A group can have multiple users but a user can belong to only one group.

How would I enforce rule so that an employee can belong only to one department?

Much appreciated

Upvotes: 0

Views: 33

Answers (1)

jpw
jpw

Reputation: 44891

With eid as a primary key you won't be able to insert more than one row for any employee as that would violate the primary key constraint. So there's no way an employee could ever belong to more than one department the way your tables are modeled.

Upvotes: 2

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