Commit Problem in ORACLE FORM 10g or the other version

hi, this morning i got a new case in commit problem.
this is the example problem.
in trigger when-button-pressed
insert into values ('aaa','bbb','ccc');
commit;

in trigger when-button-pressed
delete form where <> = < :itemName >
commit;

on that statement the oracle form can insert and delete the data in database, but some how i don't know why the database wouldn't commit that statement. to handled that problem you must replace the statement commit; into forms_ddl('commit');

example.
in trigger when-button-pressed
insert into values ('aaa','bbb','ccc');
forms_ddl('commit');

in trigger when-button-pressed
delete form where <> = < :itemName >
forms_ddl('commit');

this statement is built-in oracle form, it's can handled the issues dynamic SQL statement at runtime, include server-side PL/SQL and DDL. hmm.... i thinks just that i know how to solve the problem, if you had the other method to slove the problem please share it to us thanks :p