Check Constraints (Visual Database Tools)

A check constraint specifies the data values or formats that are acceptable in one or more columns in a table. For example, you can require the zip column of the authors table to allow only five-digit numeric entries. For more information, see Working with Constraints.

Note Note

Some databases have different functionality for check constraints. Consult your database documentation for details about how your database works with check constraints.

You can define many check constraints for a table. You create, modify, or delete each check constraint in the Check Constraints dialog box.

For information about


Attaching a check constraint to a table to specify the data values that are acceptable in one or more columns

How to: Attach a New Check Constraint to a Table or Column

Creating a constraint expression to check data for a condition

How to: Define Check Constraint Expressions

Changing the constraint expression or the options that enable or disable the constraint for specific conditions

How to: Modify Check Constraints

Applying constraints either to new data only or to existing data as well

How to: Check Existing Data When Creating a Check Constraint

Disabling a check constraint when data is added to, updated in, or deleted from a table

How to: Disable Check Constraints with INSERT and UPDATE Statements

Disabling a check constraint when your table is replicated in another database

How to: Disable Check Constraints for Replication

Removing the limitations on data values in a column

How to: Delete Check Constraints

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