constraint-column-usage-transact-sql.md

title	CONSTRAINT_COLUMN_USAGE (Transact-SQL) | Microsoft Docs
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CONSTRAINT_COLUMN_USAGE (Transact-SQL)

[!INCLUDEtsql-appliesto-ss2008-asdb-xxxx-xxx_md]

Returns one row for each column in the current database that has a constraint defined on the column. This information schema view returns information about the objects to which the current user has permissions.

To retrieve information from these views, specify the fully qualified name of **INFORMATION_SCHEMA.**view_name.

Column name	Data type	Description
TABLE_CATALOG	nvarchar(128)	Table qualifier.
TABLE_SCHEMA	nvarchar(128)	Name of schema that contains the table owner. ** Important ** Do not use INFORMATION_SCHEMA views to determine the schema of an object. The only reliable way to find the schema of a object is to query the sys.objects catalog view.
TABLE_NAME	nvarchar(128)	Table name.
COLUMN_NAME	nvarchar(128)	Column name.
CONSTRAINT_CATALOG	nvarchar(128)	Constraint qualifier.
CONSTRAINT_SCHEMA	nvarchar(128)	Name of schema that contains the constraint. ** Important ** Do not use INFORMATION_SCHEMA views to determine the schema of an object. The only reliable way to find the schema of a object is to query the sys.objects catalog view.
CONSTRAINT_NAME	nvarchar(128)	Constraint name.

See Also

System Views (Transact-SQL)
Information Schema Views (Transact-SQL)
sys.columns (Transact-SQL)
sys.objects (Transact-SQL)
sys.types (Transact-SQL)
sys.check_constraints (Transact-SQL)
sys.key_constraints (Transact-SQL)
sys.foreign_keys (Transact-SQL)