SQL Server: come ottenere il riferimento di chiave esterna da information_schema?

Question

In SQL Server, come posso ottenere il nome della tabella e della colonna referenziate da una chiave esterna?

Nota: non la tabella/colonna in cui si trova la chiave, ma la chiave a cui fa riferimento.

Esempio:

Quando la chiave [FA_MDT_ID] nella tabella [T_ALV_Ref_FilterDisplay]. si riferisce a [T_AP_Ref_Customer].[MDT_ID]

come ad esempio quando si crea un vincolo del genere:

ALTER TABLE [dbo].[T_ALV_Ref_FilterDisplay] WITH CHECK ADD CONSTRAINT [FK_T_ALV_Ref_FilterDisplay_T_AP_Ref_Customer] FOREIGN KEY([FA_MDT_ID]) 
REFERENCES [dbo].[T_AP_Ref_Customer] ([MDT_ID]) 
GO 

ho bisogno di ottenere [T_AP_Ref_Customer].[MDT_ID] quando somministrato [T_ALV_Ref_FilterAnzeige].[FA_MDT_ID] come input

Answer 1

Non importa, questa è la risposta corretta:
http://msdn.microsoft.com/en-us/library/aa175805(SQL.80).aspx

SELECT 
    KCU1.CONSTRAINT_NAME AS FK_CONSTRAINT_NAME 
    ,KCU1.TABLE_NAME AS FK_TABLE_NAME 
    ,KCU1.COLUMN_NAME AS FK_COLUMN_NAME 
    ,KCU1.ORDINAL_POSITION AS FK_ORDINAL_POSITION 
    ,KCU2.CONSTRAINT_NAME AS REFERENCED_CONSTRAINT_NAME 
    ,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 

Answer 2

Se si può vivere con utilizzando lo schema specifico di SQL Server visualizzazioni del catalogo, questa query restituirà quello che stai cercando:

SELECT 
    fk.name, 
    OBJECT_NAME(fk.parent_object_id) 'Parent table', 
    c1.name 'Parent column', 
    OBJECT_NAME(fk.referenced_object_id) 'Referenced table', 
    c2.name 'Referenced column' 
FROM 
    sys.foreign_keys fk 
INNER JOIN 
    sys.foreign_key_columns fkc ON fkc.constraint_object_id = fk.object_id 
INNER JOIN 
    sys.columns c1 ON fkc.parent_column_id = c1.column_id AND fkc.parent_object_id = c1.object_id 
INNER JOIN 
    sys.columns c2 ON fkc.referenced_column_id = c2.column_id AND fkc.referenced_object_id = c2.object_id 

Non so come - se non del tutto - è possibile ottenere le stesse informazioni da visualizzazioni INFORMATION ....

Answer 3

volevo aa versione che mi permettesse di trovare tutte le colonne "Chiave" e "ID" con/senza un vincolo. Quindi volevo tutte le colonne rispetto alla lista di tutti i PK O FK O Null, ecco la mia richiesta. Spero che aiuti qualcun altro!

SELECT 
    c.table_schema 
    ,c.table_name 
    ,c.column_name 
    ,KeyConstraints.constraint_type 
    ,KeyConstraints.constraint_schema 
    ,KeyConstraints.constraint_name 
    ,KeyConstraints.referenced_table_schema 
    ,KeyConstraints.referenced_table_name 
    ,KeyConstraints.referenced_column_name 
    ,KeyConstraints.update_rule 
    ,KeyConstraints.delete_rule 
FROM information_schema.columns AS c 
LEFT JOIN 
    (
     SELECT 
      FK.table_schema AS TABLE_SCHEMA 
      ,FK.table_name 
      ,CU.column_name 
      ,FK.constraint_type 
      ,c.constraint_schema 
      ,C.constraint_name 
      ,PK.table_schema AS REFERENCED_TABLE_SCHEMA 
      ,PK.table_name AS REFERENCED_TABLE_NAME 
      ,CCU.column_name AS REFERENCED_COLUMN_NAME 
      ,C.update_rule 
      ,C.delete_rule 
     FROM information_schema.referential_constraints AS C 

     INNER JOIN information_schema.table_constraints AS FK 
      ON C.constraint_name = FK.constraint_name 

     INNER JOIN information_schema.table_constraints AS PK 
      ON C.unique_constraint_name = PK.constraint_name 

     INNER JOIN information_schema.key_column_usage AS CU 
      ON C.constraint_name = CU.constraint_name 

     INNER JOIN information_schema.constraint_column_usage AS CCU 
      ON PK.constraint_name = CCU.constraint_name 

     WHERE (FK.constraint_type = 'FOREIGN KEY') 

     UNION 

     SELECT 
      ccu.table_schema 
      ,ccu.table_name 
      ,ccu.column_name 
      ,tc.constraint_type 
      ,ccu.constraint_schema 
      ,ccu.constraint_name 
      ,NULL 
      ,NULL 
      ,NULL 
      ,NULL 
      ,NULL 
     FROM information_schema.constraint_column_usage ccu 

     INNER JOIN information_schema.table_constraints tc 
      ON ccu.table_schema = tc.table_schema 
      AND ccu.table_name = tc.table_name 

     WHERE tc.constraint_type = 'PRIMARY KEY' 

    ) AS KeyConstraints 
    ON c.table_schema = KeyConstraints.table_schema 
    AND c.table_name = KeyConstraints.table_name 
    AND c.column_name = KeyConstraints.column_name 

WHERE c.column_name LIKE '%ID' OR c.column_name LIKE '%Key' 
ORDER BY c.table_schema 
     ,c.table_name 
     ,c.column_name 
; 

formattazione per gentile concessione di: http://www.dpriver.com/pp/sqlformat.htm