Check Constraints
Check Constraints
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.
You can define many check constraints for a table. You use the Tables property pages to create, modify, or delete each check constraint.
To | See |
---|---|
Attach a check constraint to a table to specify the data values that are acceptable in one or more columns | Attaching a New Check Constraint to a Table or Column |
Create a constraint expression to check data for a condition | Defining a Check Constraint Expression |
Change the constraint expression or the options that enable or disable the constraint for specific conditions | Modifying a Check Constraint |
Apply constraints either to new data only or to existing data as well | Checking Existing Data When Creating a Check Constraint |
Disable a check constraint when data is added to, updated in, or deleted from a table | Disabling a Check Constraint with INSERT and UPDATE Statements |
Disable a check constraint when your table is replicated in another database | Disabling a Check Constraint for Replication |
Remove the limitations on data values in a column | Deleting a Check Constraint |