Use the system package DBMS_ALERT to monitor the table

Use the system package DBMS_ALERT to monitor the table DBMS_ALERT and support asynchronous database event capturing. www.2cto.com is now testing the changes in the captured table. The test table is emp. because it is asynchronous, we need to open two SQLPLUS windows (two sessions) here to write the stored procedure in the first session as follows: (Note that the SCOTT user permission should be given first, grant execute on dbms_alert to scott) [SQL] declare v_n varchar2 (30); v_m varchar2 (100); v_ I integer; begin alias; dbms_alert.register ('emp_table_alert '); dbms_alert.waitany (v_n, v_m, v_ I); if l_ I = 0 then dbms_output.put_line ('[name:]' | Rochelle N); dbms_output.put_line ('[msg:]' | l_m); end if; dbms_alert.removeall; end;/after the stored procedure is executed, the session will be waiting... We re-open a new sqlplus and create a trigger as follows: [SQL] create or replace trigger emtring after insert or update or delete on emp begin dbms_alert.signal ('EMP _ table_alert ', to_char (sysdate, 'yyyymmdd') | ': table emp is changed'); end; in which dbms_alert.signal is used to send alerts. In this session, make some changes, for example, insert [SQL] insert into emp (empno, ename) values (1234, 'w001'); commit; Be sure to commit; Because DBMS_ALERT is based on transaction processing. once commit is enabled, the wait state of the session in the first SQLPLUS will end. The output result is as follows: [SQL] 10:18:18 SCOTT @ orcl>/[name:] EMP_TABLE_ALERT [msg:] 20121212: table emp is changed. This package is generally used in development. Various alarms in the database are captured in the application for processing.