1.  备份日志， 避免日志过快增长 no_log   /  trancate_only

BACKUP LOG realnew_DATA WITH NO_LOG
DBCC SHRINKDATABASE(realnew_DATA ,TRUNCATEONLY)
BACKUP LOG realnew_DATA WITH Truncate_ONLY

BACKUP LOG sjyh WITH NO_LOG
DBCC SHRINKDATABASE(sjyh,TRUNCATEONLY)
BACKUP LOG sjyh WITH Truncate_ONLY

2.  维持历史库数据表中的记录不超过5000条， 并将实时库中数据插入历史库
1) 使用存储过程 －－作业
CREATE procedure insert_calHistory as

if ((select count(tag_id) from CalcOUT_1_HIS)>3000)
  begin
  delete  from CalcOUT_1_HIS where tag_id in (select top 500 tag_id from CalcOUT_1_HIS order by tag_id)
  end
insert into CalcOUT_1_HIS select * from CalcOUT_1_REAL

go

然后，添加作业
   调度：每天每隔3分钟执行一次
   SQL: exec insert_calHistory

2） 使用触发器－－针对表一级的

CREATE TRIGGER  deleterecord  ON [dbo].[testtrigger]
after  INSERT
AS
IF
(SELECT COUNT(*) FROM testtrigger) >5000
BEGIN
   DELETE  FROM testtrigger   where  id  not in ( select top 300 id  from testtrigger order by id desc)
END