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
最初的问题要求将所有外键的列表放入一个高度引用的表中,以便可以删除表。
这个小查询返回将所有外键放入特定表所需的“drop foreign key”命令:
SELECT
'ALTER TABLE ['+sch.name+'].['+referencingTable.Name+'] DROP CONSTRAINT ['+foreignKey.name+']' '[DropCommand]'
FROM sys.foreign_key_columns fk
JOIN sys.tables referencingTable ON fk.parent_object_id = referencingTable.object_id
JOIN sys.schemas sch ON referencingTable.schema_id = sch.schema_id
JOIN sys.objects foreignKey ON foreignKey.object_id = fk.constraint_object_id
JOIN sys.tables referencedTable ON fk.referenced_object_id = referencedTable.object_id
WHERE referencedTable.name = 'MyTableName'
示例输出:
[DropCommand]
ALTER TABLE [dbo].[OtherTable1] DROP CONSTRAINT [FK_OtherTable1_MyTable]
ALTER TABLE [dbo].[OtherTable2] DROP CONSTRAINT [FK_OtherTable2_MyTable]
省略where -子句以获取当前数据库中所有外键的删除命令。
其他回答
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。
这将获得涉及所选表的任何外键。*假设为_FIRSTABLENAME_SECONDTABLENAME格式。
declare @tablename as varchar(MAX)
SET @tablename = 'yourtablename'
SELECT name
FROM YOURDATABASE.sys.objects
WHERE type_desc = 'FOREIGN_KEY_CONSTRAINT' and (name LIKE '%_' + @tablename + 'empdb_%' or name LIKE '%_' + @tablename )
这是更一般的形式:
SELECT name
FROM YOURDATABASE_PROD.sys.objects
WHERE type_desc = 'FOREIGN_KEY_CONSTRAINT' and name LIKE '%' + @tablename + '%' and
name NOT LIKE '[a-zA-Z0-9]' + @tablename + '%' and name NOT LIKE '%' + @tablename + '[a-zA-Z0-9]'
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…
我在2008年及以后一直在使用它。它类似于列出的其他一些解决方案,但字段名称是适当的大小写,以处理特定于大小写的(LatBin)排序。此外,您可以为它提供一个表名,并检索该表的信息。
-->>SPECIFY THE DESIRED DB
USE ???
GO
/*********************************************************************************************
LIST OUT ALL PRIMARY AND FOREIGN KEY CONSTRAINTS IN A DB OR FOR A SPECIFIED TABLE
*********************************************************************************************/
DECLARE @tblName VARCHAR(255)
/*******************/
SET @tblName = NULL-->NULL will return all PK/FK constraints for every table in the database
/*******************/
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),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 = @tblName
OR O2.name = @tblName
OR @tblName IS null)
ORDER BY PKTABLE_NAME,FKTABLE_NAME
以下的解决方案对我来说很有效:
--Eliminar las llaves foraneas
declare @query varchar(8000)
declare cursorRecorrerTabla cursor for
SELECT 'ALTER TABLE [PoaComFinH].['+sch.name+'].['+referencingTable.Name+'] DROP CONSTRAINT ['+foreignKey.name+']' 'query'
FROM PoaComFinH.sys.foreign_key_columns fk
JOIN PoaComFinH.sys.tables referencingTable ON fk.parent_object_id = referencingTable.object_id
JOIN PoaComFinH.sys.schemas sch ON referencingTable.schema_id = sch.schema_id
JOIN PoaComFinH.sys.objects foreignKey ON foreignKey.object_id = fk.constraint_object_id
JOIN PoaComFinH.sys.tables referencedTable ON fk.referenced_object_id = referencedTable.object_id
--3ro. abrir el cursor.
open cursorRecorrerTabla
fetch next from cursorRecorrerTabla
into @query
while @@fetch_status = 0
begin
--inicio cuerpo del cursor
print @query
exec(@query)
--fin cuerpo del cursor
fetch next from cursorRecorrerTabla
into @query
end
--cerrar cursor
close cursorRecorrerTabla
deallocate cursorRecorrerTabla