How to find foreign key dependencies in SQL Server?

Even Mien picture Even Mien · May 29, 2009 · Viewed 180.6k times · Source

How can I find all of the foreign key dependencies on a particular column?

What are the different alternatives (graphically in SSMS, queries/views in SQL Server, 3rd party database tools, code in .NET)?

Answer

John Sansom picture John Sansom · May 29, 2009

The following query will help to get you started. It lists all Foreign Key Relationships within the current database.

SELECT
    FK_Table = FK.TABLE_NAME,
    FK_Column = CU.COLUMN_NAME,
    PK_Table = PK.TABLE_NAME,
    PK_Column = PT.COLUMN_NAME,
    Constraint_Name = C.CONSTRAINT_NAME
FROM
    INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS C
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS FK
    ON C.CONSTRAINT_NAME = FK.CONSTRAINT_NAME
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS PK
    ON C.UNIQUE_CONSTRAINT_NAME = PK.CONSTRAINT_NAME
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CU
    ON C.CONSTRAINT_NAME = CU.CONSTRAINT_NAME
INNER JOIN (
            SELECT
                i1.TABLE_NAME,
                i2.COLUMN_NAME
            FROM
                INFORMATION_SCHEMA.TABLE_CONSTRAINTS i1
            INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE i2
                ON i1.CONSTRAINT_NAME = i2.CONSTRAINT_NAME
            WHERE
                i1.CONSTRAINT_TYPE = 'PRIMARY KEY'
           ) PT
    ON PT.TABLE_NAME = PK.TABLE_NAME

You can also view relationships graphically within SQL Server Management studio within Database Diagrams.