触发器在增量同步数据的运用.

触发器可以记录对表的添加,修改,删除,
这样可以通过触发器,记录一段时间内的表的变动的记录,把这些记录存到一个变动记录表里,
数据同步的时候,就可以读取这张变成的记录表,只需要同步变动过的记录,这样可以大大提高同步的速度.
对原表删除的操作,可以能新表做DELETE操作
对原表进行Insert 或Update操作,可以执行新建或更新操作.
下面是一个触发器(SQL SERVER 2000)的例子:

1 if exists ( select * from dbo.sysobjects where id = object_id (N ' [risk].[TRG_GUARANTEE_R_IN_HG] ' ) and OBJECTPROPERTY (id, N ' IsTrigger ' ) = 1 )
2 drop trigger [ risk ] . [ TRG_GUARANTEE_R_IN_HG ]
3 if exists ( select * from dbo.sysobjects where id = object_id (N ' [risk].[TRG_GUARANTEE_R_DEL_HG] ' ) and OBJECTPROPERTY (id, N ' IsTrigger ' ) = 1 )
4 drop trigger [ risk ] . [ TRG_GUARANTEE_R_DEL_HG ]
5 CREATE TRIGGER TRG_GUARANTEE_R_IN_HG
6 ON GUARANTEE_R
7 FOR INSERT , UPDATE
8 AS
9 UPDATE A SET ARJ_MARK = ' M ' ,CREATE_TIME = GETDATE (),USING_FLAG = ' 0000000000 '
10     FROM LOG_ENTRY_INC2 A INNER JOIN INSERTED B ON   A.ENTRY_ID = B.ENTRY_ID
11     INSERT INTO LOG_ENTRY_INC2(ENTRY_ID,ARJ_MARK,CREATE_TIME,USING_FLAG)
12     SELECT ENTRY_ID, ' M ' , GETDATE (), ' 0000000000 '
13     FROM INSERTED where ENTRY_ID NOT IN ( SELECT ENTRY_ID FROM LOG_ENTRY_INC2)
14 CREATE TRIGGER TRG_GUARANTEE_R_DEL_HG
15 ON GUARANTEE_R
16 FOR DELETE
17 AS
18 UPDATE A SET ARJ_MARK = ' D ' ,CREATE_TIME = GETDATE (),USING_FLAG = ' 0000000000 '
19     FROM LOG_ENTRY_INC2 A INNER JOIN INSERTED B ON   A.ENTRY_ID = B.ENTRY_ID
20 INSERT INTO LOG_ENTRY_INC2(ENTRY_ID,ARJ_MARK,CREATE_TIME,USING_FLAG)
21     SELECT ENTRY_ID, ' D ' , GETDATE (), ' 0000000000 '
22     FROM DELETED  where ENTRY_ID NOT IN ( SELECT ENTRY_ID FROM LOG_ENTRY_INC2)

另外需要说明的:
触发器没有updated,更新时,旧数据是deleted,新数据是inserted