PL/SQL TRIGGER Statement
The trigger statemet is a especially stored procedure.It define some event about database(such as,INSERT,UPDATE,CREATE and so on).When the special database event occur and execute the corresponse FUNCTION BLOCK.
TRIGGER Syntax:
create or replace trigger tri_name [befor|after|instead of] tri_event on table_naem|view_name|db_name [for each row] [when tri_condition] begin plsql_sentences; end tri_name;
Demo Database:
Step one:Create a table to record information for TRIGGER operator.
Create TABLE dept_log( operate_tag VARCHAR2(10), operate_time DATE );
Step two:Create a trigger on table dept.
CREATE OR REPLACE TRIGGER tri_dept BEFORE INSERT ON dept DECLARE var_tag VARCHAR2(10); BEGIN IF inserting THEN var_tag:=‘i‘; ELSIF updating THEN var_tag:=‘u‘; ELSIF deleting THEN var_tag:=‘d‘; END IF; INSERT INTO dept_log VALUES(var_tag,SYSDATE); END tri_dept;
Step three:Launch a table operator in the trigger set.
INSERT INTO dept VALUES(9,‘a‘,‘a‘);
Step four:select dept_log table information
select * from dept_log;
原文：http://www.cnblogs.com/yjhlsbnf/p/7775107.html