Error while updating or deleting a record

Question

Hi to all...
i have created atable group_master with 2 fields Group_id and Group_name
the user will specify a group_name in a text box and press save. Before commiting a seq number will be generated
inside the form procedure and it will be inserted.
The insert is working fine.
But when i select a record i.e a group_name and change it contents and commit it, it is not commiting.
when i checked the display error it showed Ora-01400 cannot insert null values into the table.
Iam not inserting a value here iam updating the group name only.
even when i delete a record it shows same error....
can any one help to solve this....
thanx in advance........

Answer 1

I have when button pressed trigger whick helps to show the lov which contains the group_id and group_name;
a := show_lov('lov27');
if a then
go_block('group_master');
execute_query;
end if;
it is correctly fetching the delected data. but propmpts a message box asking Do u want to save the record?
if i ignore it n modify the group_name and save it,still it shows unable to insert null value.
i jus want a simple way to solve this....
i want to fetch that particular record and modify or delete it.
group_id n group_name cannot be null.
i will be using Buttons for add,delete,update and save record. i will be using lov to fetch records for modification or deletion.
how to avoid the message box which prompts when i call lov with execute_query.....
* I tried Key-listval...but i didnt get any solution. i will try again....
thanx for ur replies....