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
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 |
See |
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Attaching a check constraint to a table to specify the data values that are acceptable in one or more columns |
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Creating a constraint expression to check data for a condition |
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Changing the constraint expression or the options that enable or disable the constraint for specific conditions |
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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 |
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Removing the limitations on data values in a column |