Issue with Instead of Trigger

Question

Hi everyone,
I have a view v_test . Created one instead of trigger over it. When I try to insert over the view it is throwing an error like' ORA-00036: maximum number of recursive SQL levels (50) exceeded' . Please help me how to over come from this.
Please find the below DDL Stmts;
CREATE TABLE test (id NUMBER,
name VARCHAR2(10 CHAR),
sal NUMBER,
dept_id NUMBER);
CREATE OR REPLACE VIEW v_test
IS
SELECT * FROM test;
Trigger Code:
CREATE OR REPLACE TRIGGER TR_V_TEST
INSTEAD OF INSERT ON V_test
FOR EACH ROW
BEGIN
INSERT INTO V_test VALUES(107,'VEERA',20000,30);
END;
Thanks in Advance !!
Thanks,
Vissu....

Answer 1

Vissu,
One and main scenario of mutating table error is depicted by your code only. You have created instead of Insert Trigger on view, within which again you are trying to insert on the same view i.e. you are trying to perform DML on a view which is already under transition state.
Actually, Oracle tries hard to do the task. No of attempts is the value specified for "session_cached_cursors" (which is 50 here), but fails finally to recognise the table/view state, so throws the exception ORA-00036.
In your case, instead of trigger was not required. You must understand the purpose of Instead of triggers. They are used when Multiple Tables build a view, and a DML on the view required data insertion in multiple tables. In above case, only one table is involved, so instead of trigger is not required. DML on your view can insert only in TEST table.
But in above case, handle this by avoiding the DML(Insert) on the view inside the instead of insert trigger.
Your purpose by insert on the view is to insert into TEST table only. So inside Instead of trigger,you can directly insert into table.
Hope it is clear now !!