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)
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
下面是我将使用的SQL代码。
SELECT
f.name AS 'Name of Foreign Key',
OBJECT_NAME(f.parent_object_id) AS 'Table name',
COL_NAME(fc.parent_object_id,fc.parent_column_id) AS 'Fieldname',
OBJECT_NAME(t.object_id) AS 'References Table name',
COL_NAME(t.object_id,fc.referenced_column_id) AS 'References fieldname',
'ALTER TABLE [' + OBJECT_NAME(f.parent_object_id) + '] DROP CONSTRAINT [' + f.name + ']' AS 'Delete foreign key',
'ALTER TABLE [' + OBJECT_NAME(f.parent_object_id) + '] WITH NOCHECK ADD CONSTRAINT [' +
f.name + '] FOREIGN KEY([' + COL_NAME(fc.parent_object_id,fc.parent_column_id) + ']) REFERENCES ' +
'[' + OBJECT_NAME(t.object_id) + '] ([' +
COL_NAME(t.object_id,fc.referenced_column_id) + '])' AS 'Create foreign key'
-- , delete_referential_action_desc AS 'UsesCascadeDelete'
FROM sys.foreign_keys AS f,
sys.foreign_key_columns AS fc,
sys.tables t
WHERE f.OBJECT_ID = fc.constraint_object_id
AND t.OBJECT_ID = fc.referenced_object_id
AND OBJECT_NAME(t.object_id) = 'Employees' -- Just show the FKs which reference a particular table
ORDER BY 2
这不是特别清晰的SQL,所以让我们看一个例子。
所以,假设我想删除Microsoft心爱的Northwind数据库中的Employees表,但是SQL Server告诉我一个或多个外键阻止我这样做。
上面的SQL命令将返回这些结果…
它显示有3个外键引用雇员表。换句话说,除非先删除这三个外键,否则不允许删除(删除)这个表。
在结果中,第一行是以下外键约束在结果中的显示方式。
ALTER TABLE [dbo].[Employees] WITH NOCHECK
ADD CONSTRAINT [FK_Employees_Employees] FOREIGN KEY([ReportsTo])
REFERENCES [dbo].[Employees] ([EmployeeID])
倒数第二列显示了我需要使用的SQL命令来删除这些外键之一,例如:
ALTER TABLE [Employees] DROP CONSTRAINT [FK_Employees_Employees]
...右边一列显示了创建它的SQL…
ALTER TABLE [Employees] WITH NOCHECK
ADD CONSTRAINT [FK_Employees_Employees]
FOREIGN KEY([ReportsTo]) REFERENCES [Employees] ([EmployeeID])
使用所有这些命令,您就拥有了删除相关外键所需的一切,从而可以删除表,然后再重新创建它们。
唷。希望这能有所帮助。
其他回答
上面有一些不错的答案。但我更喜欢一个问题就能得到答案。 这段代码来自sys. .Sp_helpconstraint (sys proc)
这是微软查找是否有与tbl关联的外键的方法。
--setup variables. Just change 'Customer' to tbl you want
declare @objid int,
@objname nvarchar(776)
select @objname = 'Customer'
select @objid = object_id(@objname)
if exists (select * from sys.foreign_keys where referenced_object_id = @objid)
select 'Table is referenced by foreign key' =
db_name() + '.'
+ rtrim(schema_name(ObjectProperty(parent_object_id,'schemaid')))
+ '.' + object_name(parent_object_id)
+ ': ' + object_name(object_id)
from sys.foreign_keys
where referenced_object_id = @objid
order by 1
答案看起来像这样:test_db_name.dbo。账户:FK_Account_Customer
这个答案建立在sp_fkeys的基础上,但格式化类似于sp_fkeys,适用于多个列并列出它们的顺序。
SELECT fk_obj.name AS FK_NAME,
pk_schema.name AS PKTABLE_OWNER,
pk_table.name AS PKTABLE_NAME,
pk_column.name AS PKCOLUMN_NAME,
fk_schema.name AS FKTABLE_OWNER,
fk_table.name AS FKTABLE_NAME,
fk_column.name AS FKCOLUMN_NAME,
ROW_NUMBER() over (
PARTITION BY fk_obj.name, fk_schema.name
ORDER BY fkc.constraint_column_id
) AS KEY_SEQ
FROM sys.foreign_key_columns fkc
INNER JOIN sys.objects fk_obj
ON fk_obj.object_id = fkc.constraint_object_id
INNER JOIN sys.tables fk_table
ON fk_table.object_id = fkc.parent_object_id
INNER JOIN sys.schemas fk_schema
ON fk_table.schema_id = fk_schema.schema_id
INNER JOIN sys.columns fk_column
ON fk_column.column_id = parent_column_id
AND fk_column.object_id = fk_table.object_id
INNER JOIN sys.tables pk_table
ON pk_table.object_id = fkc.referenced_object_id
INNER JOIN sys.schemas pk_schema
ON pk_table.schema_id = pk_schema.schema_id
INNER JOIN sys.columns pk_column
ON pk_column.column_id = fkc.referenced_column_id
AND pk_column.object_id = pk_table.object_id;
这里有如何计算所选Id的所有责任。只需更改@dbTableName值,@dbRowId值及其类型(如果是int,则需要在第82行中删除“..设置@sql = ..))。享受。
DECLARE @dbTableName varchar(max) = 'User'
DECLARE @dbRowId uniqueidentifier = '21d34ecd-c1fd-11e2-8545-002219a42e1c'
DECLARE @FK_ROWCOUNT int
DECLARE @SQL nvarchar(max)
DECLARE @PKTABLE_QUALIFIER sysname
DECLARE @PKTABLE_OWNER sysname
DECLARE @PKTABLE_NAME sysname
DECLARE @PKCOLUMN_NAME sysname
DECLARE @FKTABLE_QUALIFIER sysname
DECLARE @FKTABLE_OWNER sysname
DECLARE @FKTABLE_NAME sysname
DECLARE @FKCOLUMN_NAME sysname
DECLARE @UPDATE_RULE smallint
DECLARE @DELETE_RULE smallint
DECLARE @FK_NAME sysname
DECLARE @PK_NAME sysname
DECLARE @DEFERRABILITY sysname
IF OBJECT_ID('tempdb..#Temp1') IS NOT NULL
DROP TABLE #Temp1;
CREATE TABLE #Temp1 (
PKTABLE_QUALIFIER sysname,
PKTABLE_OWNER sysname,
PKTABLE_NAME sysname,
PKCOLUMN_NAME sysname,
FKTABLE_QUALIFIER sysname,
FKTABLE_OWNER sysname,
FKTABLE_NAME sysname,
FKCOLUMN_NAME sysname,
UPDATE_RULE smallint,
DELETE_RULE smallint,
FK_NAME sysname,
PK_NAME sysname,
DEFERRABILITY sysname,
FK_ROWCOUNT int
);
DECLARE FK_Counter_Cursor CURSOR FOR
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
AND O1.NAME = @dbTableName
OPEN FK_Counter_Cursor;
FETCH NEXT FROM FK_Counter_Cursor INTO @PKTABLE_QUALIFIER, @PKTABLE_OWNER, @PKTABLE_NAME, @PKCOLUMN_NAME, @FKTABLE_QUALIFIER, @FKTABLE_OWNER, @FKTABLE_NAME, @FKCOLUMN_NAME, @UPDATE_RULE, @DELETE_RULE, @FK_NAME, @PK_NAME, @DEFERRABILITY;
WHILE @@FETCH_STATUS = 0
BEGIN
SET @SQL = 'SELECT @dbCountOut = COUNT(*) FROM [' + @FKTABLE_NAME + '] WHERE [' + @FKCOLUMN_NAME + '] = ''' + CAST(@dbRowId AS varchar(max)) + '''';
EXECUTE sp_executesql @SQL, N'@dbCountOut int OUTPUT', @dbCountOut = @FK_ROWCOUNT OUTPUT;
INSERT INTO #Temp1 (PKTABLE_QUALIFIER, PKTABLE_OWNER, PKTABLE_NAME, PKCOLUMN_NAME, FKTABLE_QUALIFIER, FKTABLE_OWNER, FKTABLE_NAME, FKCOLUMN_NAME, UPDATE_RULE, DELETE_RULE, FK_NAME, PK_NAME, DEFERRABILITY, FK_ROWCOUNT) VALUES (@FKTABLE_QUALIFIER, @PKTABLE_OWNER, @PKTABLE_NAME, @PKCOLUMN_NAME, @FKTABLE_QUALIFIER, @FKTABLE_OWNER, @FKTABLE_NAME, @FKCOLUMN_NAME, @UPDATE_RULE, @DELETE_RULE, @FK_NAME, @PK_NAME, @DEFERRABILITY, @FK_ROWCOUNT)
FETCH NEXT FROM FK_Counter_Cursor INTO @PKTABLE_QUALIFIER, @PKTABLE_OWNER, @PKTABLE_NAME, @PKCOLUMN_NAME, @FKTABLE_QUALIFIER, @FKTABLE_OWNER, @FKTABLE_NAME, @FKCOLUMN_NAME, @UPDATE_RULE, @DELETE_RULE, @FK_NAME, @PK_NAME, @DEFERRABILITY;
END;
CLOSE FK_Counter_Cursor;
DEALLOCATE FK_Counter_Cursor;
GO
SELECT * FROM #Temp1
GO
试试这个:
sp_help 'TableName'
我知道这是一个很晚(非常晚)的回复,但我找到了这些简单的方法来找到所有的foreign_key_references。这是解决方案;
解决方案1:
EXEC SP_FKEYS 'MyTableName'; // It'll show you the all the information(in multiple tables) regarding to the TableName with all ForeignKey_References.
解决方案2:
EXEC SP_HELP 'MyTableName'; // It'll show all ForeignKey references in a single table.
解决方案03:
// It'll show you the Column_Name with Referenced_Table_Name
SELECT
COL_NAME(fc.parent_object_id,fc.parent_column_id) Column_Name,
OBJECT_NAME(f.parent_object_id) Table_Name
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) = 'MyTableName'
希望这对你有很大帮助。: -)