SQL Server支持禁用和启用外键约束吗?还是我唯一的选择就是放弃这些限制，然后重新创造这些限制?
当前回答
一个脚本来管理它们:这个脚本将截断和删除命令与sp_MSforeachtable结合在一起，这样您就可以避免删除和重新创建约束——只需指定需要删除而不是截断的表，为了便于度量，我还包含了一个额外的模式过滤器(在2008r2中测试)。
declare @schema nvarchar(max) = 'and Schema_Id=Schema_id(''Value'')'
declare @deletiontables nvarchar(max) = '(''TableA'',''TableB'')'
declare @truncateclause nvarchar(max) = @schema + ' and o.Name not in ' + + @deletiontables;
declare @deleteclause nvarchar(max) = @schema + ' and o.Name in ' + @deletiontables;
exec sp_MSforeachtable 'alter table ? nocheck constraint all', @whereand=@schema
exec sp_MSforeachtable 'truncate table ?', @whereand=@truncateclause
exec sp_MSforeachtable 'delete from ?', @whereand=@deleteclause
exec sp_MSforeachtable 'alter table ? with check check constraint all', @whereand=@schema
其他回答
如果你感兴趣，我有一个更有用的版本。我从这里提取了一些代码，一个网站的链接不再活跃。我修改了它，以允许存储过程中有一个表数组，并在执行所有语句之前填充删除、截断和添加语句。这使您可以控制决定哪些表需要截断。
/****** Object: UserDefinedTableType [util].[typ_objects_for_managing] Script Date: 03/04/2016 16:42:55 ******/
CREATE TYPE [util].[typ_objects_for_managing] AS TABLE(
[schema] [sysname] NOT NULL,
[object] [sysname] NOT NULL
)
GO
create procedure [util].[truncate_table_with_constraints]
@objects_for_managing util.typ_objects_for_managing readonly
--@schema sysname
--,@table sysname
as
--select
-- @table = 'TABLE',
-- @schema = 'SCHEMA'
declare @exec_table as table (ordinal int identity (1,1), statement nvarchar(4000), primary key (ordinal));
--print '/*Drop Foreign Key Statements for ['+@schema+'].['+@table+']*/'
insert into @exec_table (statement)
select
'ALTER TABLE ['+SCHEMA_NAME(o.schema_id)+'].['+ o.name+'] DROP CONSTRAINT ['+fk.name+']'
from sys.foreign_keys fk
inner join sys.objects o
on fk.parent_object_id = o.object_id
where
exists (
select * from @objects_for_managing chk
where
chk.[schema] = SCHEMA_NAME(o.schema_id)
and
chk.[object] = o.name
)
;
--o.name = @table and
--SCHEMA_NAME(o.schema_id) = @schema
insert into @exec_table (statement)
select
'TRUNCATE TABLE ' + src.[schema] + '.' + src.[object]
from @objects_for_managing src
;
--print '/*Create Foreign Key Statements for ['+@schema+'].['+@table+']*/'
insert into @exec_table (statement)
select 'ALTER TABLE ['+SCHEMA_NAME(o.schema_id)+'].['+o.name+'] ADD CONSTRAINT ['+fk.name+'] FOREIGN KEY (['+c.name+'])
REFERENCES ['+SCHEMA_NAME(refob.schema_id)+'].['+refob.name+'](['+refcol.name+'])'
from sys.foreign_key_columns fkc
inner join sys.foreign_keys fk
on fkc.constraint_object_id = fk.object_id
inner join sys.objects o
on fk.parent_object_id = o.object_id
inner join sys.columns c
on fkc.parent_column_id = c.column_id and
o.object_id = c.object_id
inner join sys.objects refob
on fkc.referenced_object_id = refob.object_id
inner join sys.columns refcol
on fkc.referenced_column_id = refcol.column_id and
fkc.referenced_object_id = refcol.object_id
where
exists (
select * from @objects_for_managing chk
where
chk.[schema] = SCHEMA_NAME(o.schema_id)
and
chk.[object] = o.name
)
;
--o.name = @table and
--SCHEMA_NAME(o.schema_id) = @schema
declare @looper int , @total_records int, @sql_exec nvarchar(4000)
select @looper = 1, @total_records = count(*) from @exec_table;
while @looper <= @total_records
begin
select @sql_exec = (select statement from @exec_table where ordinal =@looper)
exec sp_executesql @sql_exec
print @sql_exec
set @looper = @looper + 1
end
要禁用约束，您可以使用NOCHECK更改表
ALTER TABLE [TABLE_NAME] NOCHECK CONSTRAINT [ALL|CONSTRAINT_NAME]
要使您必须使用双重检查:
ALTER TABLE [TABLE_NAME] WITH CHECK CHECK CONSTRAINT [ALL|CONSTRAINT_NAME]
启用时请注意双重CHECK CHECK。 ALL表示表中的所有约束。
一旦完成，如果您需要检查状态，使用这个脚本列出约束状态。会很有帮助:
SELECT (CASE
WHEN OBJECTPROPERTY(CONSTID, 'CNSTISDISABLED') = 0 THEN 'ENABLED'
ELSE 'DISABLED'
END) AS STATUS,
OBJECT_NAME(CONSTID) AS CONSTRAINT_NAME,
OBJECT_NAME(FKEYID) AS TABLE_NAME,
COL_NAME(FKEYID, FKEY) AS COLUMN_NAME,
OBJECT_NAME(RKEYID) AS REFERENCED_TABLE_NAME,
COL_NAME(RKEYID, RKEY) AS REFERENCED_COLUMN_NAME
FROM SYSFOREIGNKEYS
ORDER BY TABLE_NAME, CONSTRAINT_NAME,REFERENCED_TABLE_NAME, KEYNO
您可以暂时禁用表上的约束，进行工作，然后重新构建它们。
这里有一个简单的方法…
禁用所有索引，包括主键，这将禁用所有外键，然后重新启用主键，以便您可以使用它们…
DECLARE @sql AS NVARCHAR(max)=''
select @sql = @sql +
'ALTER INDEX ALL ON [' + t.[name] + '] DISABLE;'+CHAR(13)
from
sys.tables t
where type='u'
select @sql = @sql +
'ALTER INDEX ' + i.[name] + ' ON [' + t.[name] + '] REBUILD;'+CHAR(13)
from
sys.key_constraints i
join
sys.tables t on i.parent_object_id=t.object_id
where
i.type='PK'
exec dbo.sp_executesql @sql;
go
[做一些事情，比如加载数据]
然后重新启用和重建索引……
DECLARE @sql AS NVARCHAR(max)=''
select @sql = @sql +
'ALTER INDEX ALL ON [' + t.[name] + '] REBUILD;'+CHAR(13)
from
sys.tables t
where type='u'
exec dbo.sp_executesql @sql;
go
第一篇文章:)
对于OP, kristof的解决方案是有效的，除非在大删除上存在大量数据和事务日志气球问题。此外，即使有空闲的tlog存储空间，由于删除写入tlog，对于具有数亿行的表，操作可能会花费非常长的时间。
我经常使用一系列游标来截断和重新加载我们的大型生产数据库之一的大型副本。设计的解决方案支持多个模式、多个外键列，最重要的是可以在SSIS中使用。
It involves creation of three staging tables (real tables) to house the DROP, CREATE, and CHECK FK scripts, creation and insertion of those scripts into the tables, and then looping over the tables and executing them. The attached script is four parts: 1.) creation and storage of the scripts in the three staging (real) tables, 2.) execution of the drop FK scripts via a cursor one by one, 3.) Using sp_MSforeachtable to truncate all the tables in the database other than our three staging tables and 4.) execution of the create FK and check FK scripts at the end of your ETL SSIS package.
在SSIS中的Execute SQL任务中运行脚本创建部分。在第二个执行SQL任务中运行“execute Drop FK Scripts”部分。将截断脚本放在第三个Execute SQL任务中，然后在控制流末尾的最后一个Execute SQL任务(如果需要的话可以是两个)中附加CREATE和CHECK脚本之前，执行您需要执行的任何其他ETL过程。
当重新应用外键失败时，在实际表中存储脚本被证明是非常宝贵的，因为您可以从sync_CreateFK中选择*，复制/粘贴到查询窗口中，一次运行一个，并在发现失败/仍然无法重新应用的数据时修复数据问题。
如果脚本失败，请不要再次重新运行脚本，否则您很可能会丢失一些创建和检查fk脚本，因为在创建要执行的脚本之前，我们的staging表会被删除并重新创建。
----------------------------------------------------------------------------
1)
/*
Author: Denmach
DateCreated: 2014-04-23
Purpose: Generates SQL statements to DROP, ADD, and CHECK existing constraints for a
database. Stores scripts in tables on target database for execution. Executes
those stored scripts via independent cursors.
DateModified:
ModifiedBy
Comments: This will eliminate deletes and the T-log ballooning associated with it.
*/
DECLARE @schema_name SYSNAME;
DECLARE @table_name SYSNAME;
DECLARE @constraint_name SYSNAME;
DECLARE @constraint_object_id INT;
DECLARE @referenced_object_name SYSNAME;
DECLARE @is_disabled BIT;
DECLARE @is_not_for_replication BIT;
DECLARE @is_not_trusted BIT;
DECLARE @delete_referential_action TINYINT;
DECLARE @update_referential_action TINYINT;
DECLARE @tsql NVARCHAR(4000);
DECLARE @tsql2 NVARCHAR(4000);
DECLARE @fkCol SYSNAME;
DECLARE @pkCol SYSNAME;
DECLARE @col1 BIT;
DECLARE @action CHAR(6);
DECLARE @referenced_schema_name SYSNAME;
--------------------------------Generate scripts to drop all foreign keys in a database --------------------------------
IF OBJECT_ID('dbo.sync_dropFK') IS NOT NULL
DROP TABLE sync_dropFK
CREATE TABLE sync_dropFK
(
ID INT IDENTITY (1,1) NOT NULL
, Script NVARCHAR(4000)
)
DECLARE FKcursor CURSOR FOR
SELECT
OBJECT_SCHEMA_NAME(parent_object_id)
, OBJECT_NAME(parent_object_id)
, name
FROM
sys.foreign_keys WITH (NOLOCK)
ORDER BY
1,2;
OPEN FKcursor;
FETCH NEXT FROM FKcursor INTO
@schema_name
, @table_name
, @constraint_name
WHILE @@FETCH_STATUS = 0
BEGIN
SET @tsql = 'ALTER TABLE '
+ QUOTENAME(@schema_name)
+ '.'
+ QUOTENAME(@table_name)
+ ' DROP CONSTRAINT '
+ QUOTENAME(@constraint_name)
+ ';';
--PRINT @tsql;
INSERT sync_dropFK (
Script
)
VALUES (
@tsql
)
FETCH NEXT FROM FKcursor INTO
@schema_name
, @table_name
, @constraint_name
;
END;
CLOSE FKcursor;
DEALLOCATE FKcursor;
---------------Generate scripts to create all existing foreign keys in a database --------------------------------
----------------------------------------------------------------------------------------------------------
IF OBJECT_ID('dbo.sync_createFK') IS NOT NULL
DROP TABLE sync_createFK
CREATE TABLE sync_createFK
(
ID INT IDENTITY (1,1) NOT NULL
, Script NVARCHAR(4000)
)
IF OBJECT_ID('dbo.sync_createCHECK') IS NOT NULL
DROP TABLE sync_createCHECK
CREATE TABLE sync_createCHECK
(
ID INT IDENTITY (1,1) NOT NULL
, Script NVARCHAR(4000)
)
DECLARE FKcursor CURSOR FOR
SELECT
OBJECT_SCHEMA_NAME(parent_object_id)
, OBJECT_NAME(parent_object_id)
, name
, OBJECT_NAME(referenced_object_id)
, OBJECT_ID
, is_disabled
, is_not_for_replication
, is_not_trusted
, delete_referential_action
, update_referential_action
, OBJECT_SCHEMA_NAME(referenced_object_id)
FROM
sys.foreign_keys WITH (NOLOCK)
ORDER BY
1,2;
OPEN FKcursor;
FETCH NEXT FROM FKcursor INTO
@schema_name
, @table_name
, @constraint_name
, @referenced_object_name
, @constraint_object_id
, @is_disabled
, @is_not_for_replication
, @is_not_trusted
, @delete_referential_action
, @update_referential_action
, @referenced_schema_name;
WHILE @@FETCH_STATUS = 0
BEGIN
BEGIN
SET @tsql = 'ALTER TABLE '
+ QUOTENAME(@schema_name)
+ '.'
+ QUOTENAME(@table_name)
+ CASE
@is_not_trusted
WHEN 0 THEN ' WITH CHECK '
ELSE ' WITH NOCHECK '
END
+ ' ADD CONSTRAINT '
+ QUOTENAME(@constraint_name)
+ ' FOREIGN KEY (';
SET @tsql2 = '';
DECLARE ColumnCursor CURSOR FOR
SELECT
COL_NAME(fk.parent_object_id
, fkc.parent_column_id)
, COL_NAME(fk.referenced_object_id
, fkc.referenced_column_id)
FROM
sys.foreign_keys fk WITH (NOLOCK)
INNER JOIN sys.foreign_key_columns fkc WITH (NOLOCK) ON fk.[object_id] = fkc.constraint_object_id
WHERE
fkc.constraint_object_id = @constraint_object_id
ORDER BY
fkc.constraint_column_id;
OPEN ColumnCursor;
SET @col1 = 1;
FETCH NEXT FROM ColumnCursor INTO @fkCol, @pkCol;
WHILE @@FETCH_STATUS = 0
BEGIN
IF (@col1 = 1)
SET @col1 = 0;
ELSE
BEGIN
SET @tsql = @tsql + ',';
SET @tsql2 = @tsql2 + ',';
END;
SET @tsql = @tsql + QUOTENAME(@fkCol);
SET @tsql2 = @tsql2 + QUOTENAME(@pkCol);
--PRINT '@tsql = ' + @tsql
--PRINT '@tsql2 = ' + @tsql2
FETCH NEXT FROM ColumnCursor INTO @fkCol, @pkCol;
--PRINT 'FK Column ' + @fkCol
--PRINT 'PK Column ' + @pkCol
END;
CLOSE ColumnCursor;
DEALLOCATE ColumnCursor;
SET @tsql = @tsql + ' ) REFERENCES '
+ QUOTENAME(@referenced_schema_name)
+ '.'
+ QUOTENAME(@referenced_object_name)
+ ' ('
+ @tsql2 + ')';
SET @tsql = @tsql
+ ' ON UPDATE '
+
CASE @update_referential_action
WHEN 0 THEN 'NO ACTION '
WHEN 1 THEN 'CASCADE '
WHEN 2 THEN 'SET NULL '
ELSE 'SET DEFAULT '
END
+ ' ON DELETE '
+
CASE @delete_referential_action
WHEN 0 THEN 'NO ACTION '
WHEN 1 THEN 'CASCADE '
WHEN 2 THEN 'SET NULL '
ELSE 'SET DEFAULT '
END
+
CASE @is_not_for_replication
WHEN 1 THEN ' NOT FOR REPLICATION '
ELSE ''
END
+ ';';
END;
-- PRINT @tsql
INSERT sync_createFK
(
Script
)
VALUES (
@tsql
)
-------------------Generate CHECK CONSTRAINT scripts for a database ------------------------------
----------------------------------------------------------------------------------------------------------
BEGIN
SET @tsql = 'ALTER TABLE '
+ QUOTENAME(@schema_name)
+ '.'
+ QUOTENAME(@table_name)
+
CASE @is_disabled
WHEN 0 THEN ' CHECK '
ELSE ' NOCHECK '
END
+ 'CONSTRAINT '
+ QUOTENAME(@constraint_name)
+ ';';
--PRINT @tsql;
INSERT sync_createCHECK
(
Script
)
VALUES (
@tsql
)
END;
FETCH NEXT FROM FKcursor INTO
@schema_name
, @table_name
, @constraint_name
, @referenced_object_name
, @constraint_object_id
, @is_disabled
, @is_not_for_replication
, @is_not_trusted
, @delete_referential_action
, @update_referential_action
, @referenced_schema_name;
END;
CLOSE FKcursor;
DEALLOCATE FKcursor;
--SELECT * FROM sync_DropFK
--SELECT * FROM sync_CreateFK
--SELECT * FROM sync_CreateCHECK
---------------------------------------------------------------------------
2.)
-----------------------------------------------------------------------------------------------------------------
----------------------------execute Drop FK Scripts --------------------------------------------------
DECLARE @scriptD NVARCHAR(4000)
DECLARE DropFKCursor CURSOR FOR
SELECT Script
FROM sync_dropFK WITH (NOLOCK)
OPEN DropFKCursor
FETCH NEXT FROM DropFKCursor
INTO @scriptD
WHILE @@FETCH_STATUS = 0
BEGIN
--PRINT @scriptD
EXEC (@scriptD)
FETCH NEXT FROM DropFKCursor
INTO @scriptD
END
CLOSE DropFKCursor
DEALLOCATE DropFKCursor
--------------------------------------------------------------------------------
3.)
------------------------------------------------------------------------------------------------------------------
----------------------------Truncate all tables in the database other than our staging tables --------------------
------------------------------------------------------------------------------------------------------------------
EXEC sp_MSforeachtable 'IF OBJECT_ID(''?'') NOT IN
(
ISNULL(OBJECT_ID(''dbo.sync_createCHECK''),0),
ISNULL(OBJECT_ID(''dbo.sync_createFK''),0),
ISNULL(OBJECT_ID(''dbo.sync_dropFK''),0)
)
BEGIN TRY
TRUNCATE TABLE ?
END TRY
BEGIN CATCH
PRINT ''Truncation failed on''+ ? +''
END CATCH;'
GO
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------
----------------------------execute Create FK Scripts and CHECK CONSTRAINT Scripts---------------
----------------------------tack me at the end of the ETL in a SQL task-------------------------
-------------------------------------------------------------------------------------------------
DECLARE @scriptC NVARCHAR(4000)
DECLARE CreateFKCursor CURSOR FOR
SELECT Script
FROM sync_createFK WITH (NOLOCK)
OPEN CreateFKCursor
FETCH NEXT FROM CreateFKCursor
INTO @scriptC
WHILE @@FETCH_STATUS = 0
BEGIN
--PRINT @scriptC
EXEC (@scriptC)
FETCH NEXT FROM CreateFKCursor
INTO @scriptC
END
CLOSE CreateFKCursor
DEALLOCATE CreateFKCursor
-------------------------------------------------------------------------------------------------
DECLARE @scriptCh NVARCHAR(4000)
DECLARE CreateCHECKCursor CURSOR FOR
SELECT Script
FROM sync_createCHECK WITH (NOLOCK)
OPEN CreateCHECKCursor
FETCH NEXT FROM CreateCHECKCursor
INTO @scriptCh
WHILE @@FETCH_STATUS = 0
BEGIN
--PRINT @scriptCh
EXEC (@scriptCh)
FETCH NEXT FROM CreateCHECKCursor
INTO @scriptCh
END
CLOSE CreateCHECKCursor
DEALLOCATE CreateCHECKCursor
右键单击表设计，进入“关系”，在左侧窗格中选择外键，在右侧窗格中，将强制外键约束设置为“Yes”(启用外键约束)或“No”(禁用外键约束)。
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