利用触发实现三个数据库中的某个表的同步

利用触发器实现Database1、Database2、Database3三个数据库的TableName的同步。

参考与数据库复制比较（合并复制与触发器实现同步）

代码：

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[tr_Database3]') and  type='TR')
drop trigger [dbo].[tr_Database3]
go
create trigger tr_Database3 on tableName for update,insert,delete
as
begin
declare @insertcount int,@deletecount int
select @insertcount=count(*) from Inserted
select @deletecount=count(*) from deleted
---insert插入---
if (@insertcount>0 and @deletecount=0)
begin
alter table Database1.dbo.tableName disable trigger tr_Database1
insert into Database1.dbo.tableName(
    field1,field2.field3.field4)
select field1,field2.field3.field4
from inserted
alter table Database1.dbo.tableName enable trigger tr_Database1
alter table Database2.dbo.tableName disable trigger tr_Database2
insert into Database2.dbo.tableName(field1,field2.field3.field4)
select field1,field2.field3.field4
from inserted
alter table Database2.dbo.tableName enable trigger tr_Database2

end
---delete删除----
else if(@deletecount>0 and @insertcount=0)
begin
alter table Database1.dbo.tableName disable trigger tr_Database1
alter table Database2.dbo.tableName disable trigger tr_Database2
begin
delete Database2.dbo.tableName where Database2.dbo.tableName.account in(select account from deleted)
delete Database1.dbo.tableName where Database1.dbo.tableName.account in(select account from deleted)
end
alter table Database1.dbo.tableName enable trigger tr_Database1
alter table Database2.dbo.tableName enable trigger tr_Database2

end
---update更新---
else if(@deletecount>0 and @insertcount>0)
begin
alter table Database1.dbo.tableName disable trigger tr_Database1
alter table Database2.dbo.tableName disable trigger tr_Database2
begin
update Database2.dbo.tableName set Database2.dbo.tableName.field1=d.field1,Database2.dbo.tableName.field2=d.field2,Database2.dbo.tableName.field3=d.field3,
from inserted d where Database2.dbo.tableName.field4=d.field4
update Database1.dbo.tableName set Database1.dbo.tableName.field1=d.field1,Database1.dbo.tableName.field2=d.field2,Database1.dbo.tableName.field3=d.field3,

from inserted d where Database1.dbo.tableName.field4=d.field4
end
alter table Database1.dbo.tableName enable trigger tr_Database1
alter table Database2.dbo.tableName enable trigger tr_Database2
end
end