Export (0) Print Expand All  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 replica