How to Retrieve Referenced Table and Column Information from Foreign Keys in SQL Server using `INFORMATION_SCHEMA`?

Retrieving Foreign Key References Using Information_schema

In SQL Server, extracting the referenced table and column name associated with a foreign key can be achieved using a query on the information_schema views.

Query:

SELECT 
    KCU1.CONSTRAINT_SCHEMA AS FK_CONSTRAINT_SCHEMA, 
    KCU1.CONSTRAINT_NAME AS FK_CONSTRAINT_NAME, 
    KCU1.TABLE_SCHEMA AS FK_TABLE_SCHEMA, 
    KCU1.TABLE_NAME AS FK_TABLE_NAME, 
    KCU1.COLUMN_NAME AS FK_COLUMN_NAME, 
    KCU1.ORDINAL_POSITION AS FK_ORDINAL_POSITION, 
    KCU2.CONSTRAINT_SCHEMA AS REFERENCED_CONSTRAINT_SCHEMA, 
    KCU2.CONSTRAINT_NAME AS REFERENCED_CONSTRAINT_NAME, 
    KCU2.TABLE_SCHEMA AS REFERENCED_TABLE_SCHEMA, 
    KCU2.TABLE_NAME AS REFERENCED_TABLE_NAME, 
    KCU2.COLUMN_NAME AS REFERENCED_COLUMN_NAME, 
    KCU2.ORDINAL_POSITION AS REFERENCED_ORDINAL_POSITION 
FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS AS RC 

INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KCU1 
    ON KCU1.CONSTRAINT_CATALOG = RC.CONSTRAINT_CATALOG  
    AND KCU1.CONSTRAINT_SCHEMA = RC.CONSTRAINT_SCHEMA 
    AND KCU1.CONSTRAINT_NAME = RC.CONSTRAINT_NAME 

INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KCU2 
    ON KCU2.CONSTRAINT_CATALOG = RC.UNIQUE_CONSTRAINT_CATALOG  
    AND KCU2.CONSTRAINT_SCHEMA = RC.UNIQUE_CONSTRAINT_SCHEMA 
    AND KCU2.CONSTRAINT_NAME = RC.UNIQUE_CONSTRAINT_NAME 
    AND KCU2.ORDINAL_POSITION = KCU1.ORDINAL_POSITION

This query retrieves the foreign key constraint schema, name, table schema, table name, column name, and ordinal position for both the referencing and referenced tables.

Example:

To retrieve the referenced table and column for the foreign key FA_MDT_ID in the table T_ALV_Ref_FilterDisplay, use the following query:

SELECT 
    FK_CONSTRAINT_SCHEMA,
    FK_CONSTRAINT_NAME,
    FK_TABLE_SCHEMA,
    FK_TABLE_NAME,
    FK_COLUMN_NAME,
    REFERENCED_TABLE_SCHEMA,
    REFERENCED_TABLE_NAME,
    REFERENCED_COLUMN_NAME
FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS AS RC

INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KCU1
    ON KCU1.CONSTRAINT_CATALOG = RC.CONSTRAINT_CATALOG
    AND KCU1.CONSTRAINT_SCHEMA = RC.CONSTRAINT_SCHEMA
    AND KCU1.CONSTRAINT_NAME = RC.CONSTRAINT_NAME

INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KCU2
    ON KCU2.CONSTRAINT_CATALOG = RC.UNIQUE_CONSTRAINT_CATALOG
    AND KCU2.CONSTRAINT_SCHEMA = RC.UNIQUE_CONSTRAINT_SCHEMA
    AND KCU2.CONSTRAINT_NAME = RC.UNIQUE_CONSTRAINT_NAME
    AND KCU2.ORDINAL_POSITION = KCU1.ORDINAL_POSITION
WHERE
    KCU1.FK_TABLE_NAME = 'T_ALV_Ref_FilterDisplay'
    AND KCU1.FK_COLUMN_NAME = 'FA_MDT_ID';

The result will provide the referenced table name (T_AP_Ref_Customer) and column name (MDT_ID).

The above is the detailed content of How to Retrieve Referenced Table and Column Information from Foreign Keys in SQL Server using `INFORMATION_SCHEMA`?. For more information, please follow other related articles on the PHP Chinese website!