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
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
其他回答
--Drop and Recreate Foreign Key Constraints
SET NOCOUNT ON
DECLARE @table TABLE(
RowId INT PRIMARY KEY IDENTITY(1, 1),
ForeignKeyConstraintName NVARCHAR(200),
ForeignKeyConstraintTableSchema NVARCHAR(200),
ForeignKeyConstraintTableName NVARCHAR(200),
ForeignKeyConstraintColumnName NVARCHAR(200),
PrimaryKeyConstraintName NVARCHAR(200),
PrimaryKeyConstraintTableSchema NVARCHAR(200),
PrimaryKeyConstraintTableName NVARCHAR(200),
PrimaryKeyConstraintColumnName NVARCHAR(200)
)
INSERT INTO @table(ForeignKeyConstraintName, ForeignKeyConstraintTableSchema, ForeignKeyConstraintTableName, ForeignKeyConstraintColumnName)
SELECT
U.CONSTRAINT_NAME,
U.TABLE_SCHEMA,
U.TABLE_NAME,
U.COLUMN_NAME
FROM
INFORMATION_SCHEMA.KEY_COLUMN_USAGE U
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS C
ON U.CONSTRAINT_NAME = C.CONSTRAINT_NAME
WHERE
C.CONSTRAINT_TYPE = 'FOREIGN KEY'
UPDATE @table SET
PrimaryKeyConstraintName = UNIQUE_CONSTRAINT_NAME
FROM
@table T
INNER JOIN INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS R
ON T.ForeignKeyConstraintName = R.CONSTRAINT_NAME
UPDATE @table SET
PrimaryKeyConstraintTableSchema = TABLE_SCHEMA,
PrimaryKeyConstraintTableName = TABLE_NAME
FROM @table T
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS C
ON T.PrimaryKeyConstraintName = C.CONSTRAINT_NAME
UPDATE @table SET
PrimaryKeyConstraintColumnName = COLUMN_NAME
FROM @table T
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE U
ON T.PrimaryKeyConstraintName = U.CONSTRAINT_NAME
--SELECT * FROM @table
--DROP CONSTRAINT:
SELECT
'
ALTER TABLE [' + ForeignKeyConstraintTableSchema + '].[' + ForeignKeyConstraintTableName + ']
DROP CONSTRAINT ' + ForeignKeyConstraintName + '
GO'
FROM
@table
--ADD CONSTRAINT:
SELECT
'
ALTER TABLE [' + ForeignKeyConstraintTableSchema + '].[' + ForeignKeyConstraintTableName + ']
ADD CONSTRAINT ' + ForeignKeyConstraintName + ' FOREIGN KEY(' + ForeignKeyConstraintColumnName + ') REFERENCES [' + PrimaryKeyConstraintTableSchema + '].[' + PrimaryKeyConstraintTableName + '](' + PrimaryKeyConstraintColumnName + ')
GO'
FROM
@table
GO
我同意你的观点,哈姆林。当您使用SSIS传输数据或想要复制数据时,似乎很有必要暂时禁用或删除外键约束,然后重新启用或重新创建它们。在这些情况下,引用完整性不是问题,因为它已经在源数据库中进行了维护。所以,这件事你可以放心。
SQL-92标准允许将约束声明为DEFERRABLE,以便在事务范围内(隐式或显式)延迟它。遗憾的是,SQL Server仍然缺少这个SQL-92功能。
对我来说,将约束更改为NOCHECK类似于动态更改数据库结构——删除约束当然是这样——这是需要避免的(例如,用户需要增加特权)。
标记为“905”的答案看起来不错,但不能工作。
下面的方法对我很有效。不能禁用任何主键、唯一键或默认约束。事实上,如果“sp_helpconstraint”在status_enabled中显示“n/a”-意味着它不能被启用/禁用。
生成脚本为DISABLE
select 'ALTER TABLE ' + object_name(id) + ' NOCHECK CONSTRAINT [' + object_name(constid) + ']'
from sys.sysconstraints
where status & 0x4813 = 0x813 order by object_name(id)
——生成脚本以启用
select 'ALTER TABLE ' + object_name(id) + ' CHECK CONSTRAINT [' + object_name(constid) + ']'
from sys.sysconstraints
where status & 0x4813 = 0x813 order by object_name(id)
你可以使用以下命令轻松切换CONSTRAINT: 修改表TableName不检查约束所有
完成交易后,不要忘记使用以下方法再次开启: 修改表表名检查约束全部
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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