CONSTRAINT_COLUMN_USAGE (Transact-SQL)

CONSTRAINT_COLUMN_USAGE (Transact-SQL)
SQL Server 2005

SQL Server 2008 Books Online (October 2009)

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 an object is to query the sys.objects catalog view or the OBJECT_SCHEMA_NAME function.
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 an object is to query the sys.objects catalog view or the OBJECT_SCHEMA_NAME function.
CONSTRAINT_NAME	nvarchar(128)	Constraint name.

Examples

The following example returns columns from the CHECK_CONSTRAINTS and CONSTRAINT_COLUMN_USAGE views to display information about the constraint and the column on which the constraint is defined.

USE AdventureWorks;
GO

SELECT ccu.TABLE_SCHEMA, ccu.TABLE_NAME, ccu.COLUMN_NAME, cc.CONSTRAINT_SCHEMA, cc.CONSTRAINT_NAME, cc.CHECK_CLAUSE
FROM INFORMATION_SCHEMA.CHECK_CONSTRAINTS AS cc
INNER JOIN INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE AS ccu
    ON cc.CONSTRAINT_NAME = ccu.CONSTRAINT_NAME;

The following example returns all constraints in the database that reference the column 'StartDate'.

USE AdventureWorks;
GO

SELECT TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME, CONSTRAINT_SCHEMA, CONSTRAINT_NAME
FROM INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE
WHERE COLUMN_NAME = 'StartDate';

Reference

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