Transact-SQL Reference

sysconstraints

Contains mappings of constraints to the objects that own the constraints. This system catalog is stored in each database.

Column name	Data type	Description
constid	int	Constraint number.
id	int	ID of the table that owns the constraint.
colid	smallint	ID of the column on which the constraint is defined, 0 if a table constraint.
spare1	tinyint	Reserved.
status	int	Bitmap indicating the status. Possible values include: 1 = PRIMARY KEY constraint. 2 = UNIQUE KEY constraint. 3 = FOREIGN KEY constraint. 4 = CHECK constraint. 5 = DEFAULT constraint. 16 = Column-level constraint. 32 = Table-level constraint.
actions	int	Reserved.
error	int	Reserved.