禁用启用数据库外键约束

-- 禁用所有约束
EXEC sp_msforeachtable
 @command1=N'ALTER TABLE ? NOCHECK CONSTRAINT ALL'

-- 删除无外键约束的表中的数据
EXEC sp_msforeachtable
 @command1=N'TRUNCATE TABLE ?',
 @whereand=N'AND NOT EXISTS(
 SELECT rkeyid FROM dbo.sysforeignkeys 
 WHERE rkeyid=O.id)
 AND EXISTS( 
 SELECT rows FROM dbo.sysindexes 
 WHERE id=O.id 
 AND rows>0
 AND indid<2)'

-- 删除有外键约束的表中的数据
EXEC sp_msforeachtable
 @command1=N'DELETE ?',
 @whereand=N'AND EXISTS( 
 SELECT rows FROM dbo.sysindexes 
 WHERE id=O.id 
 AND rows>0
 AND indid<2)'

-- 启用所有约束
EXEC sp_msforeachtable
 @command1=N'ALTER TABLE ? CHECK CONSTRAINT ALL'

mayb