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In SQL can a table have both primary keys composite keys?

Time:09-21

In SQL Server, can a table have primary key on 1 column and then composite keys on other two or more columns?

CodePudding user response:

Yes.

A table can have more than one Key, and a Key has one or more key columns.

In SQL Server you create a Key with any of a UNIQUE CONSTRAINT, a PRIMARY KEY CONSTRAINT, or a UNIQUE INDEX. A table can at most one PRIMARY KEY CONSTRAINT, but can have any number of UNIQUE CONSTRAINTs or UNIQUE INDEXs.

So yes, a table can have a PRIMARY KEY on one column, and a composite UNIQUE INDEX or UNIQUE CONSTRAINT.

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