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A check constraint expression can have multiple conditions.Here is an example that shows a check constraint that has multiple conditions: Remember in order for SQL Server to reject a record, the final outcome of the logical expression for the check constraint needs to evaluate to FALSE.This can be done by using the ALTER TABLE statement.

You don’t have to create constraints that only check the values of a single column.A check constraint consists of a logical expression to identify what is a valid expression.The logical expression may be a single expression like “ Salary Here I have a CHECK clause that is associated with the Salary column. If you create a column level constraint, you can only refer to the column name in the logical expression of your check constraint.You can create constraints that check values in multiple columns at the same time.For instance, if I wanted to create a single constraint that checked both the Salary, and Salary Type constraints I created above I could use the following code: This single constraint does the same thing as the above two constraints.

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