SQL Server:如何从information_schema获取外键引用？

Question

在SQL Server中,如何从外键获取引用的表+列名？

注意:不是键所在的表/列,而是键所引用的键.

例:

当[FA_MDT_ID]表中的键[T_ALV_Ref_FilterDisplay].是指[T_AP_Ref_Customer].[MDT_ID]

例如在创建这样的约束时:

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

[T_AP_Ref_Customer].[MDT_ID] 当[T_ALV_Ref_FilterAnzeige].[FA_MDT_ID]作为输入给出时我需要得到

Answer 1

没关系,这是正确答案:http:
//msdn.microsoft.com/en-us/library/aa175805(SQL.80).aspx

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 

Answer 2

如果您可以使用SQL Server特定的架构目录视图,则此查询将返回您要查找的内容:

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

不确定 - 如果有的话 - 你可以从INFORMATION_SCHEMA视图中获得相同的信息....