Constraints : Constraints « Constraints « SQL Server / T-SQL Tutorial






  1. SQL Server / T-SQL Tutorial
  2. Constraints
  3. Constraints
Constraints are used by SQL Server to enforce column data integrity.
Both primary and foreign keys are forms of constraints.
Other forms of constraints used for a column include:
UNIQUE constraints enforce uniqueness within a table on non-primary key columns.
DEFAULT constraints can be used when you do not know the value of a column in a row when it is first inserted into a table.
CHECK constraints are used to define the data format and values allowed for a column.








7.1.Constraints
7.1.1.Constraints
7.1.2.Disabling and Enabling a Constraint
7.1.3.Disable checking on all constraints
7.1.4.Enable checking on all constraints
7.1.5.Dropping a Constraint from a Table