Oracle Forms

Hi,

I have some problems on implementing master-detail block.
How can I avoid showing the unique constraint in detail block?
ORA-00001: unique constraint (SCOTT.PK_DTABLE) violated.

I use an LOV in the detail block to select the ItemID.
I would like to remove the ItemID which has been selected before from the LOV.
So the user won't be able to choose twice.
But, the LOV is based on Query, not static record group.
How can I do this?

- If possible, can I manually check the condition of unique violation?
I want to show with my 'own language' alert if it happen.
- Can I do merging to the detail record which share the same ItemID?
I mean, by calculating the quantity of the item.
Or have the form to do updating, instead of inserting, when found duplicate ItemID in detail?


Another problem,
Can I ask the Form to remove or ignore the detail record with specific criteria
before inserting it to the database?
i.e, automatically ignore or (remove) the detail record where Quantity = 0.
I know, we can use when-validate-item trigger to inform the user.
But I'd like to simply remove the "zero-quantity" item from being inserted.

Any help would be grateful.

Many thanks,


Imelda