You can specify error messages.
The syntax to append error message to error:
raise_application_error(<exception code>,<error message>);
You can only specify error messages for exceptions that have already been assigned a code.
procedure p_validateSalary(i_empNo_nr NUMBER, i_new_sal_tx NUMBER)
is
v_current_sal NUMBER;
e_increaseTooLarge EXCEPTION;
pragma exception_init (e_increaseTooLarge,-20999)
begin
select salary into v_current_sal
from emp
where empNo=i_empNo_nr;
if (i_newsal_nr/v_current_sal)*100>300
then
raise_application_error (-20999, 'Cannot triple salary for employee #'||i_empNo);
end if;
exception
when e_increaseTooLarge then
insert into t_logError ...
raise;
end;