CODEWITHSUNDEEP
sqlsql-server-2008foreign-keysconstraints
Ocelot20
Ocelot20

Reputation: 10800

SQL Script to find Foreign keys to a specific table?

Is there a query that will get me foreign keys directed at a specific table column? For example, say I had these three tables:

__________
|Table A |
----------
|Id      |
----------

___________
|Table B  |
-----------
|Id       |
|TableAId | (Foreign Key to TableA.Id)
-----------

___________
|Table C  |
-----------
|Id       |
|TableAId | (Foreign Key to TableA.Id)
-----------

I need a query along the lines of "Select * Foreign Keys directed at TableA.Id" that returned "Table C: TableAId", "Table B: TableAId". I'm browsing through some of the INFORMATION_SCHEMA system views, and it seems like I can easily see what foreign keys belong to Table A, or Table B individually, but I can't find where it says "Table C has a foreign key to Table A" specifically. I can figure out the specifics of the query, I just can't find the views I'm looking for (or I'm glossing over them). Any help would be appreciated.

Upvotes: 19

Views: 23567

Answers (2)

Tomer Bar-Shlomo
Tomer Bar-Shlomo

Reputation: 441

Added dynamic drop and create on dbo scheme.

DECLARE @l varchar(1) = char(13);
DECLARE @referenced_object_id varchar(MAX) = 'Replace_With_PK_Table_Name';

SELECT 
    fk.name AS ForeignKey,
    OBJECT_NAME(fk.parent_object_id) AS TableName,
    COL_NAME(fkc.parent_object_id,
    fkc.parent_column_id) AS ColumnName,
    OBJECT_NAME (fk.referenced_object_id) AS ReferenceTableName,
    COL_NAME(fkc.referenced_object_id,
    fkc.referenced_column_id) AS ReferenceColumnName,
    'ALTER TABLE [dbo].['+OBJECT_NAME(fk.parent_object_id)+'] DROP CONSTRAINT ['+fk.name+'];' DropFK,
    'ALTER TABLE [dbo].['+OBJECT_NAME(fk.parent_object_id)+']  WITH NOCHECK ADD  CONSTRAINT ['+fk.name+'] FOREIGN KEY(['+COL_NAME(fkc.referenced_object_id,
    fkc.referenced_column_id)+'])'+ @l +
    ' REFERENCES [dbo].['+OBJECT_NAME(fk.referenced_object_id)+'] (['+COL_NAME(fkc.referenced_object_id,
    fkc.referenced_column_id)+'])'+ @l +
    ' ON UPDATE CASCADE'+ @l +
    ' ON DELETE CASCADE;'+ @l +
    'ALTER TABLE [dbo].['+OBJECT_NAME(fk.parent_object_id)+'] CHECK CONSTRAINT ['+fk.name+'];' CreateFK
FROM 
    sys.foreign_keys AS fk
    INNER JOIN sys.foreign_key_columns AS fkc ON fk.OBJECT_ID = fkc.constraint_object_id
    WHERE OBJECT_NAME(fk.referenced_object_id)=@referenced_object_id

Upvotes: 0

Michael Fredrickson
Michael Fredrickson

Reputation: 37388

Courtesy of Pinal Dave:

SELECT 
    f.name AS ForeignKey,
    OBJECT_NAME(f.parent_object_id) AS TableName,
    COL_NAME(fc.parent_object_id,
    fc.parent_column_id) AS ColumnName,
    OBJECT_NAME (f.referenced_object_id) AS ReferenceTableName,
    COL_NAME(fc.referenced_object_id,
    fc.referenced_column_id) AS ReferenceColumnName
FROM 
    sys.foreign_keys AS f
    INNER JOIN sys.foreign_key_columns AS fc ON f.OBJECT_ID = fc.constraint_object_id

Upvotes: 40

Related Questions