【IT168 技术文档】SQLServer 2000与Oracle 8i相比，SQLServer级联删除有太多的限制，下面就为您介绍SQLServer级联删除的实现方法，供您参考。
表内自关联不支持级联删除和级联更新
一个表内在有多个列同时关联于另一个表时，不支持多个级联删除
还有什么循环级联删除限制，等等
.......
一大堆限制，如果要迁移Oracle到SqlServer麻烦多多，特别对于用于构造树型结构的表内自关联(比如部门表)的级联删除特别讨厌
考虑来考虑去，对于SqlServer不能支持的诸多SQLServer级联删除只有采用最原始的方法，彻底不用外键关联，而是用触发器来解决
以下是经过验证的触发器实现范例(自关联例子)
放弃外键关联后所有的完整性检查都要通过触发器实现
--DELETE 级联删除，先删除，再删除所有级联的记录，采用递归触发器，当然要求数据库支持递归触发器功能开启(数据库属性设置中开启他)，不过SqlServer只支持32级的递归啊
以下是代码片段：
IF EXISTS (SELECT NAME FROM SYSOBJECTS
WHERE NAME = 'DEL_DOCUMENTTYPE_001' AND TYPE = 'TR')
DROP TRIGGER DEL_DOCUMENTTYPE_001
GO
CREATE TRIGGER DEL_DOCUMENTTYPE_001
ON dbo.DOCUMENTTYPE
FOR DELETE
AS
IF (SELECT COUNT(*) FROM DELETED) > 0
DELETE FROM dbo.DOCUMENTTYPE WHERE UPNO IN (SELECT NO FROM DELETED)
GO
WHERE NAME = 'DEL_DOCUMENTTYPE_001' AND TYPE = 'TR')
DROP TRIGGER DEL_DOCUMENTTYPE_001
GO
CREATE TRIGGER DEL_DOCUMENTTYPE_001
ON dbo.DOCUMENTTYPE
FOR DELETE
AS
IF (SELECT COUNT(*) FROM DELETED) > 0
DELETE FROM dbo.DOCUMENTTYPE WHERE UPNO IN (SELECT NO FROM DELETED)
GO
