Working with Constraints

Constraints are rules that the database server enforces for you.

For details about working with constraints, see the following topics.

To	See
Ensure no duplicate values are entered in specific columns	How to: Create Unique Constraints
Change the columns that the constraint is attached to, change the constraint name, or set additional properties for the constraint	How to: Modify Unique Constraints
Remove the requirement for uniqueness for values entered in the column	How to: Delete Unique Constraints
Create a constraint expression to check data for a condition	How to: Define Check Constraint Expressions
Apply constraints either to new data only or to existing data as well	How to: Check Existing Data When Creating a Check Constraint
Attach 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
Disable a check constraint when your table is replicated in another database	How to: Disable Check Constraints for Replication
Disable 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
Change the constraint expression or the options that enable or disable the constraint for specific conditions	How to: Modify Check Constraints
Remove the limitations on data values in a column	How to: Delete Check Constraints
Show the properties for a selected check constraint in the Properties window.	How to: Show Check Constraint Properties

See Also