Constraints

Ahmad Yaseen

Commonly used SQL Server Constraints: NOT NULL, UNIQUE and PRIMARY KEY

October 25, 2017 by

SQL Server Constraints are predefined rules and restrictions that are enforced in a single column or multiple columns, regarding the values allowed in the columns, to maintain the integrity, accuracy, and reliability of that column’s data. In other words, if the inserted data meets the constraint rule, it will be inserted successfully. If the inserted data violates the defined constraint, the insert operation will be aborted.

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