Oracle中实现后台自动执行的定时操作(定时器)
1．确保Oracle的工作模式答应启动任务队列治理器:
Oracle定时执行“Job Queue”的后台程序是SNP进程，而要启动SNP进程，首先要确保整个系统的模式是可以启动SNP进程的，这需要以DBA的身份去执行如下命令：
svrmgrl> alter system enable restricted session;
或sql> alter system disenable restricted session;
利用如上命令更改系统的会话方式为disenable restricted，为SNP的启动创造条件。
2. Dbms_job.submit的语法为：
dbms_job.submit( job out binary_integer,
whatinarchar2,
next_date indate，
intervalinvarchar2,
no_parseinboolean);
其中：
●job：输出变量，是此任务在任务队列中的编号；
●what：执行的任务的名称及其输入参数；
●next_date：任务执行的时间；
●interval：任务执行的时间间隔。
将任务加入到任务队列之前，要确定执行任务的数据库用户，若用户是scott, 则需要确保该用户拥有执行包dbms_job的权限；若没有，需要以DBA的身份将权利授予scott用户：
svrmgrl> grant execute on dbms_job to scott;
3. 实例：
Java代码
SQL> declare
2 n number;
3 begin
4 dbms_job.submit(n, 'PKG_RPT_REVERSAL.P_FORM4_REVERSAL_ENTRY;',SYSDATE, null);
5 commit;
6 end;
7 /
L/SQL procedure successfully completed
SQL> declare
2 n number;
3 begin
4 dbms_job.submit(n, 'PKG_RPT_REVERSAL.P_FORM4_REVERSAL_ENTRY;',SYSDATE, null);
5 commit;
6 end;
7 /
PL/SQL procedure successfully completed
PKG_RPT_REVERSAL.P_FORM4_REVERSAL_ENTRY的代码如下：
Java代码
/*
* insert data into t_prod_tmp table
*/
PROCEDURE P_INSERT_PROD_TMP(I_PROCESS_DATE IN DATE)AS
M_START_DATE date;
M_END_DATE date;
BEGIN
select trunc(I_PROCESS_DATE, 'MONTH') into M_START_DATE from dual;
M_END_DATE := ADD_MONTHS(M_START_DATE, 1);
INSERT INTO T_PROD_TMP
(POLICY_ID, CHANGE_ID, SERVICE_ID, FINISH_TIME)
SELECT PC.POLICY_ID,PC.CHANGE_ID,PC.SERVICE_ID,PC.FINISH_TIME
FROM T_POLICY_CHANGE PC, T_ACTUARY_FORM4_TRANSACTION FT
WHERE PC.CHANGE_STATUS = '4' ----撤销状态
AND PC.SERVICE_ID = FT.TRANS_ID
AND FT.TRANS_STATUS = '1' -----有效Service
AND PC.FINISH_TIME >= M_START_DATE
AND PC.FINISH_TIME < M_END_DATE
AND PC.WITHDRAW_TIME <= PC.FINISH_TIME ---Service Undo操作时间应该先于finish_time
ORDER BY PC.POLICY_ID,PC.FINISH_TIME;
END P_INSERT_PROD_TMP;
/*
* Function Entry
*/
PROCEDURE P_FORM4_REVERSAL_ENTRY AS
BEGIN
---- insert data about service reversal Trans into T_PROD_TMP Table-----
P_INSERT_PROD_TMP(SYSDATE);
---some actions on database are as follows...
END P_FORM4_REVERSAL_ENTRY;
end PKG_RPT_REVERSAL;
/*
* insert data into t_prod_tmp table
*/
PROCEDURE P_INSERT_PROD_TMP(I_PROCESS_DATE IN DATE)AS
M_START_DATE date;
M_END_DATE date;
BEGIN
select trunc(I_PROCESS_DATE, 'MONTH') into M_START_DATE from dual;
M_END_DATE := ADD_MONTHS(M_START_DATE, 1);
INSERT INTO T_PROD_TMP
(POLICY_ID, CHANGE_ID, SERVICE_ID, FINISH_TIME)
SELECT PC.POLICY_ID,PC.CHANGE_ID,PC.SERVICE_ID,PC.FINISH_TIME
FROM T_POLICY_CHANGE PC, T_ACTUARY_FORM4_TRANSACTION FT
WHERE PC.CHANGE_STATUS = '4' ----撤销状态
AND PC.SERVICE_ID = FT.TRANS_ID
AND FT.TRANS_STATUS = '1' -----有效Service
AND PC.FINISH_TIME >= M_START_DATE
AND PC.FINISH_TIME < M_END_DATE
AND PC.WITHDRAW_TIME <= PC.FINISH_TIME ---Service Undo操作时间应该先于finish_time
ORDER BY PC.POLICY_ID,PC.FINISH_TIME;
END P_INSERT_PROD_TMP;
/*
* Function Entry
*/
PROCEDURE P_FORM4_REVERSAL_ENTRY AS
BEGIN
---- insert data about service reversal Trans into T_PROD_TMP Table-----
P_INSERT_PROD_TMP(SYSDATE);
---some actions on database are as follows...
END P_FORM4_REVERSAL_ENTRY;
end PKG_RPT_REVERSAL;
查看一下job执行情况：
SQL> select job,next_date,next_sec,failures,broken from user_jobs;
JOB NEXT_DATE NEXT_SEC FAILURES BROKEN
---------- ----------- ------------------------ ---------- ------
1726 1/1/4000 00:00:00 N
2103 1/1/4000 00:00:00 N
2601 1/1/4000 00:00:00 N
4021 12/1/2009 00:00:00 0 N
6227 11/30/2009 13:22:22 0 N
6228 11/30/2009 13:22:17 0 N
973 1/1/4000 00:00:00 17 Y
2977 12/7/2009 00:00:00 0 N
2976 12/7/2009 00:00:00 0 N
3579 1/1/4000 00:00:00 16 Y
13063 12/1/2009 00:00:00 0 N
13149 12/1/2009 00:00:00 0 N
19683 11/30/2009 13:22:22 0 N
21929 11/30/2009 13:22:17 0 N
21930 11/30/2009 13:22:22 0 N
如果事务到预定时间并没有执行，排除是过程本身的问题外，可能的原因是初始化参数job_queue_processes值为0或没有设置。用alter system set job_queue_processes=n;（n>0）做好设置。注：job_queue_processes最大值为1000