Pragma exception_init

Question

HI,
I want log the ORA-00942 error through exception.
declare
v_no number;
v_error exception;
pragma exception_init(v_error,-942);
begin
select empno into v_no from notable;
exception
when v_error then
insert into log values('no table');
end;
when ever i execute the program ,instead of logging error in log table ..it is raising error that ' ORA-942 TABLE OR VIEW DOESN'T EXIST'. i want log this message in logtable instead of raising error
Thanks

Answer 1

Hi,
only a short addition/illustration to/of the idea provided by SY
-- Create Log-Table
drop table log;
Create table log ( msg varchar2(4000 char));
drop table notable;
-- P compiles without table "NOTABLE" because of the use of dynamic sql see
-- Solomon Yakobsons post above
create or replace
procedure p
as
     v_no number;
     v_stmt varchar2(2000) := 'select empno from notable';
     v_error exception;
     pragma exception_init(v_error,-942);
begin
     EXECUTE IMMEDIATE v_stmt into v_no;
     insert into log values('j = '|| (nvl(to_char(v_no), '<<NULL>>')));
exception
when v_error then
     insert into log values('no table');
        -- you somehow need the following commit to make the changes in the log-table permanent;
        -- other way could be combining this method with autonomous transactions
     commit;
when others then
     insert into log values(substr(dbms_utility.format_error_stack,1,4000));
        -- commit; /*????*/
end;
-- 1. table "NOTABLE" doesn't exist => "no table" in log-table
truncate table log;
exec p;
select * from log;
-- 2. table "NOTABLE" exists but is empty => "ORA-01403: no data found"
create table notable (empno Number);
truncate table log;
-- writes log-message "ORA-01403: no data found" into log-table
exec p;
select * from log;
-- 3. one row in "NOTABLE"; "all is well"; here "j = 1"
-- insert first row into notable
insert into notable (empno) values (1);
commit; -- not needed because of the following truncate
-- writes value of the selection into the log-table
truncate table log;
exec p;
select * from log;
-- 4. two rows in notable => "ORA-01422: exact fetch returns more than requested number of rows"
-- insert second row
insert into notable (empno) values (2);
commit;
truncate table log;
-- writes error
exec p;
select * from log;So the "COMMIT" in the exception-handler may cause some trouble, if you just write without commiting here,
a calling stored procedure might rollback your changes, which will be very misleading. The use of AUTONOMOUS TRANSACTIONS
could get complicated too, please be careful here.
See [url http://tkyte.blogspot.de/search?q=autonomous+transactions] Tom Kyte Blog about AUTONOMOUS TRANSACTIONS, EXCEPTION WHEN OTHERS, ... why and when autonomous transactions can help you and if you should rethink your strategy about not reraising the error. Your business logic is broken in this case, isn't it? So why carry on?
Regards
stratmo
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>
Uuuups, seems that there is some work to do for you;-)