Insert and Update Useing Oracle developer 2000 as front-end with MySQL

[haji rachid]

Hi,
I have a problem when I want to insert or update a row Useing Oracle developer 2000 as front-end with MySQL.

this is the script of my form test:
begin
insert into tab_localite values(20,'TEST');
end;

for the first clic there's no message and no effect
for the second clic, it give me this message:
FRM-40735: Le déclencheur WHEN-BUTTON-PRESSED a détecté une exception ORA-30021 non traitée.

can you help me please