oracle怎么建立定时任务

Oracle提供了DBMS_SCHEDULER包来创建和管理定时任务。下面是一个例子，展示了如何在Oracle中创建一个每天执行一次的定时任务：

1. 创建一个作业(Job)

BEGIN
    DBMS_SCHEDULER.CREATE_JOB (
        job_name        => 'my_job_name',
        job_type        => 'PLSQL_BLOCK',
        job_action      => 'BEGIN my_procedure; END;',
        start_date      => SYSTIMESTAMP,
        repeat_interval => 'FREQ=DAILY; BYHOUR=0; BYMINUTE=0; BYSECOND=0;',
        end_date        => NULL,
        enabled         => TRUE,
        comments        => 'My job comments'
    );
END;
/

2. 创建一个程序(Program)

BEGIN
    DBMS_SCHEDULER.CREATE_PROGRAM (
        program_name     => 'my_program_name',
        program_type     => 'PLSQL_BLOCK',
        program_action   => 'BEGIN my_procedure; END;',
        number_of_arguments => 0,
        enabled          => TRUE,
        comments         => 'My program comments'
    );
END;
/

3. 创建一个凭证(Credential)

BEGIN
    DBMS_SCHEDULER.CREATE_CREDENTIAL (
        credential_name => 'my_credential_name',
        username        => 'my_username',
        password        => 'my_password',
        comments        => 'My credential comments'
    );
END;
/

4. 将凭证(Credential)授权给程序(Program)

BEGIN
    DBMS_SCHEDULER.GRANT_PROGRAM_ACCESS (
        grantee_name      => 'my_grantee_name',
        program_name      => 'my_program_name',
        privilege         => 'EXECUTE',
        credential_name   => 'my_credential_name',
        comments          => 'My grant comments'
    );
END;
/

这样就可以在Oracle中创建一个每天执行一次的定时任务了。