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sys-foreign-key-columns-transact-sql.md

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title description author ms.author ms.date ms.service ms.subservice ms.topic f1_keywords helpviewer_keywords dev_langs monikerRange
sys.foreign_key_columns (Transact-SQL)
sys.foreign_key_columns (Transact-SQL)
rwestMSFT
randolphwest
04/05/2022
sql
system-objects
reference
sys.foreign_key_columns
foreign_key_columns
sys.foreign_key_columns_TSQL
foreign_key_columns_TSQL
sys.foreign_key_columns catalog view
TSQL
>=aps-pdw-2016||=azuresqldb-current||=azure-sqldw-latest||>=sql-server-2016||>=sql-server-linux-2017||=azuresqldb-mi-current||=fabric

sys.foreign_key_columns (Transact-SQL)

[!INCLUDE sql-asdb-asdbmi-asa-pdw-fabricdw]

Contains a row for each column, or set of columns, that comprise a foreign key.

Column name Data type Description
constraint_object_id int ID of the FOREIGN KEY constraint.
constraint_column_id int ID of the column, or set of columns, that comprise the FOREIGN KEY (1..n where n is the number of columns).
parent_object_id int ID of the parent of the constraint, which is the referencing object.
parent_column_id int ID of the parent column, which is the referencing column.
referenced_object_id int ID of the referenced object, which has the candidate key.
referenced_column_id int ID of the referenced column (candidate key column).

Permissions

[!INCLUDEssCatViewPerm] For more information, see Metadata Visibility Configuration.

Example query

The following Transact-SQL query retrieves all foreign keys in the database, including their related tables and columns.

SELECT fk.name AS ForeignKeyName
    , t_parent.name AS ParentTableName
    , c_parent.name AS ParentColumnName
    , t_child.name AS ReferencedTableName
    , c_child.name AS ReferencedColumnName
FROM sys.foreign_keys fk 
INNER JOIN sys.foreign_key_columns fkc
    ON fkc.constraint_object_id = fk.object_id
INNER JOIN sys.tables t_parent
    ON t_parent.object_id = fk.parent_object_id
INNER JOIN sys.columns c_parent
    ON fkc.parent_column_id = c_parent.column_id  
    AND c_parent.object_id = t_parent.object_id 
INNER JOIN sys.tables t_child
    ON t_child.object_id = fk.referenced_object_id
INNER JOIN sys.columns c_child
    ON c_child.object_id = t_child.object_id
    AND fkc.referenced_column_id = c_child.column_id
ORDER BY t_parent.name, c_parent.name;

See also