我需要在SQL Server数据库中删除一个高度引用的表。我如何才能得到所有外键约束的列表,我将需要删除以便删除表?

(SQL比在管理工作室的GUI中点击更可取)


当前回答

SQL Server中所有引用给定表的外键列表:

您可以通过以下查询获得引用表名和列名…

SELECT 
   OBJECT_NAME(f.parent_object_id) TableName,
   COL_NAME(fc.parent_object_id,fc.parent_column_id) ColName
FROM 
   sys.foreign_keys AS f
INNER JOIN 
   sys.foreign_key_columns AS fc 
      ON f.OBJECT_ID = fc.constraint_object_id
INNER JOIN 
   sys.tables t 
      ON t.OBJECT_ID = fc.referenced_object_id
WHERE 
   OBJECT_NAME (f.referenced_object_id) = 'TableName'

下面的截图让你理解…

其他回答

以下是我认为在SQL Server 2016中处理这种情况的最佳实践。

你必须列出外键使用:

EXEC sp_fkeys 'TableName'

在这里你可以看到fk的全部信息。注意列FKTABLE_NAME, FKCOLUMN_NAME, FK_NAME, UPDATE_RULE, DELETE_RULE是你需要删除外键并在截断后再次实现它们的信息。

你可以组织一个脚本如下:

-- EXEC sp_fkeys 'TableName'

-- DROP CONSTRAINTS: I drop one, here drop every constraint you desire. 
BEGIN TRANSACTION
GO
ALTER TABLE dbo.TableName
    DROP CONSTRAINT IF EXISTS FK_TableName_OtherTable
GO
ALTER TABLE dbo.TableName SET (LOCK_ESCALATION = TABLE)
GO
COMMIT

-- TRUNCATE 
BEGIN TRANSACTION
TRUNCATE TABLE TableName
GO
COMMIT


-- RECREATE CONSTRAINTS: I recreate 1, here recreate every fk you desire
BEGIN TRANSACTION
GO
ALTER TABLE dbo.TableName SET (LOCK_ESCALATION = TABLE)
GO

ALTER TABLE dbo.TableName ADD CONSTRAINT
    FK_TableName_OtherTable FOREIGN KEY
    (
    Id_FK
    ) REFERENCES dbo.OtherTable
    (
    Id
    ) ON UPDATE  NO ACTION 
     ON DELETE  NO ACTION 
GO
COMMIT

** UPDATE_RULE和DELETE_RULE的值可以在sp_fkeys的文档中看到:

确定数据库中所有表的主键和唯一键…

这应该列出所有的约束条件,在最后你可以放入过滤器

/* CAST IS DONE , SO THAT OUTPUT INTEXT FILE REMAINS WITH SCREEN LIMIT*/
WITH   ALL_KEYS_IN_TABLE (CONSTRAINT_NAME,CONSTRAINT_TYPE,PARENT_TABLE_NAME,PARENT_COL_NAME,PARENT_COL_NAME_DATA_TYPE,REFERENCE_TABLE_NAME,REFERENCE_COL_NAME) 
AS
(
SELECT  CONSTRAINT_NAME= CAST (PKnUKEY.name AS VARCHAR(30)) ,
        CONSTRAINT_TYPE=CAST (PKnUKEY.type_desc AS VARCHAR(30)) ,
        PARENT_TABLE_NAME=CAST (PKnUTable.name AS VARCHAR(30)) ,
        PARENT_COL_NAME=CAST ( PKnUKEYCol.name AS VARCHAR(30)) ,
        PARENT_COL_NAME_DATA_TYPE=  oParentColDtl.DATA_TYPE,        
        REFERENCE_TABLE_NAME='' ,
        REFERENCE_COL_NAME='' 

FROM sys.key_constraints as PKnUKEY
    INNER JOIN sys.tables as PKnUTable
            ON PKnUTable.object_id = PKnUKEY.parent_object_id
    INNER JOIN sys.index_columns as PKnUColIdx
            ON PKnUColIdx.object_id = PKnUTable.object_id
            AND PKnUColIdx.index_id = PKnUKEY.unique_index_id
    INNER JOIN sys.columns as PKnUKEYCol
            ON PKnUKEYCol.object_id = PKnUTable.object_id
            AND PKnUKEYCol.column_id = PKnUColIdx.column_id
     INNER JOIN INFORMATION_SCHEMA.COLUMNS oParentColDtl
            ON oParentColDtl.TABLE_NAME=PKnUTable.name
            AND oParentColDtl.COLUMN_NAME=PKnUKEYCol.name
UNION ALL
SELECT  CONSTRAINT_NAME= CAST (oConstraint.name AS VARCHAR(30)) ,
        CONSTRAINT_TYPE='FK',
        PARENT_TABLE_NAME=CAST (oParent.name AS VARCHAR(30)) ,
        PARENT_COL_NAME=CAST ( oParentCol.name AS VARCHAR(30)) ,
        PARENT_COL_NAME_DATA_TYPE= oParentColDtl.DATA_TYPE,     
        REFERENCE_TABLE_NAME=CAST ( oReference.name AS VARCHAR(30)) ,
        REFERENCE_COL_NAME=CAST (oReferenceCol.name AS VARCHAR(30)) 
FROM sys.foreign_key_columns FKC
    INNER JOIN sys.sysobjects oConstraint
            ON FKC.constraint_object_id=oConstraint.id 
    INNER JOIN sys.sysobjects oParent
            ON FKC.parent_object_id=oParent.id
    INNER JOIN sys.all_columns oParentCol
            ON FKC.parent_object_id=oParentCol.object_id /* ID of the object to which this column belongs.*/
            AND FKC.parent_column_id=oParentCol.column_id/* ID of the column. Is unique within the object.Column IDs might not be sequential.*/
    INNER JOIN sys.sysobjects oReference
            ON FKC.referenced_object_id=oReference.id
    INNER JOIN INFORMATION_SCHEMA.COLUMNS oParentColDtl
            ON oParentColDtl.TABLE_NAME=oParent.name
            AND oParentColDtl.COLUMN_NAME=oParentCol.name
    INNER JOIN sys.all_columns oReferenceCol
            ON FKC.referenced_object_id=oReferenceCol.object_id /* ID of the object to which this column belongs.*/
            AND FKC.referenced_column_id=oReferenceCol.column_id/* ID of the column. Is unique within the object.Column IDs might not be sequential.*/

)

select * from   ALL_KEYS_IN_TABLE
where   
    PARENT_TABLE_NAME  in ('YOUR_TABLE_NAME') 
    or REFERENCE_TABLE_NAME  in ('YOUR_TABLE_NAME')
ORDER BY PARENT_TABLE_NAME,CONSTRAINT_NAME;

如需参考,请阅读http://blogs.msdn.com/b/sqltips/archive/2005/09/16/469136.aspx

 SELECT OBJECT_NAME(fk.parent_object_id) as ReferencingTable, 
        OBJECT_NAME(fk.constraint_object_id) as [FKContraint]
  FROM sys.foreign_key_columns as fk
 WHERE fk.referenced_object_id = OBJECT_ID('ReferencedTable', 'U')

这只显示了外键约束的关系。我的数据库显然早于FK约束。一些表使用触发器来强制引用完整性,有时除了一个类似命名的列来指示关系之外什么都没有(根本没有引用完整性)。

幸运的是,我们有一个一致的命名场景,所以我能够找到引用表 观点是这样的:

SELECT OBJECT_NAME(object_id) from sys.columns where name like 'client_id'

我使用这个选择作为生成一个脚本的基础,做我需要做的事情 相关的表格。

也试一试。

EXEC sp_fkeys 'tableName', 'schemaName'

使用sp_fkeys,不仅可以通过pk表名和模式过滤结果,还可以通过fk表名和模式过滤结果。链接

SELECT PKTABLE_QUALIFIER = CONVERT(SYSNAME,DB_NAME()),
       PKTABLE_OWNER = CONVERT(SYSNAME,SCHEMA_NAME(O1.SCHEMA_ID)),
       PKTABLE_NAME = CONVERT(SYSNAME,O1.NAME),
       PKCOLUMN_NAME = CONVERT(SYSNAME,C1.NAME),
       FKTABLE_QUALIFIER = CONVERT(SYSNAME,DB_NAME()),
       FKTABLE_OWNER = CONVERT(SYSNAME,SCHEMA_NAME(O2.SCHEMA_ID)),
       FKTABLE_NAME = CONVERT(SYSNAME,O2.NAME),
       FKCOLUMN_NAME = CONVERT(SYSNAME,C2.NAME),
       -- Force the column to be non-nullable (see SQL BU 325751)
       --KEY_SEQ             = isnull(convert(smallint,k.constraint_column_id), sysconv(smallint,0)),
       UPDATE_RULE = CONVERT(SMALLINT,CASE OBJECTPROPERTY(F.OBJECT_ID,'CnstIsUpdateCascade') 
                                        WHEN 1 THEN 0
                                        ELSE 1
                                      END),
       DELETE_RULE = CONVERT(SMALLINT,CASE OBJECTPROPERTY(F.OBJECT_ID,'CnstIsDeleteCascade') 
                                        WHEN 1 THEN 0
                                        ELSE 1
                                      END),
       FK_NAME = CONVERT(SYSNAME,OBJECT_NAME(F.OBJECT_ID)),
       PK_NAME = CONVERT(SYSNAME,I.NAME),
       DEFERRABILITY = CONVERT(SMALLINT,7)   -- SQL_NOT_DEFERRABLE
FROM   SYS.ALL_OBJECTS O1,
       SYS.ALL_OBJECTS O2,
       SYS.ALL_COLUMNS C1,
       SYS.ALL_COLUMNS C2,
       SYS.FOREIGN_KEYS F
       INNER JOIN SYS.FOREIGN_KEY_COLUMNS K
         ON (K.CONSTRAINT_OBJECT_ID = F.OBJECT_ID)
       INNER JOIN SYS.INDEXES I
         ON (F.REFERENCED_OBJECT_ID = I.OBJECT_ID
             AND F.KEY_INDEX_ID = I.INDEX_ID)
WHERE  O1.OBJECT_ID = F.REFERENCED_OBJECT_ID
       AND O2.OBJECT_ID = F.PARENT_OBJECT_ID
       AND C1.OBJECT_ID = F.REFERENCED_OBJECT_ID
       AND C2.OBJECT_ID = F.PARENT_OBJECT_ID
       AND C1.COLUMN_ID = K.REFERENCED_COLUMN_ID
       AND C2.COLUMN_ID = K.PARENT_COLUMN_ID