Working with Constraints

Constraints are rules that the database server enforces for you.

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



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

Other Resources

Working with Keys

Working with Relationships