Re: RPG Native IO with SQL unique constraint

On 08/09/2009, at 11:50 AM, Steven Harrison wrote:

With a unique constraint across OrderID : ProductID : Quantity ie.
Each
product in an order can have different quantity values but no two
records can have the same quantity.

Perhaps I'm missing something but what is the point of that
constraint? It just seems stupid to me. What it will allow is an order
with say:
       7 widgets
       2 framistats
       2 more widgets
but it won't allow
       7 widgets
       2 framistats
       7 more widgets

or your example of 3 line items for the same product with different
quantities. Why allow any of that?

That just seems silly. Removing the quantity from the constraint may
not help either. That will have the effect of only allowing a single
quantity for a given product (however that does make more sense to
me). I would remove both the product ID and quantity and set the
constraint to OrderID and LineID.

If you must have that constraint in place (or at least have ProductID
included in the constraint) then surely the code should consolidate
multiple quantities for the same product into a single line item?

Failing that the user will need to be educated as to the constraint
requirement and be instructed to make the edits in a sequence that
does not invalidate the constraint. Onerous to say the least.


Regards,
Simon Coulter.
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