[ic] mv_metadata & derived (calculated) data

[David Kelly]

On Thu, 13 Jun 2002 3:48 am, Ed LaFrance wrote:
> At 10:34 AM 06/12/2002 -0400, you wrote:
> >Quoting David Kelly (david@zeald.com):
> > > Is it possible to put in mv_metadata an entry that will allow you to
> >
> > display a
> >
> > > entry with the table editor tag that is derived (calculated) from other
> > > fields from the table?
> > >
> > > For Example:
> > >
> > > Under the 'products' entry in the mv_metadata.asc file I can set in the
> > > 'options' field what fields I want the item_edit page to display.   Is
> > > it possible to put an entry in there that is the sum of two other
> > > fields
> > >
> > > e.g.
> > > A
> > > B
> > > C=(A+B)
> > >
> > > I realise that I can simulate the effect of this by just writing my own
> >
> > custom
> >
> > > item edit page.   But I am trying to create a more generic and reusable
> > > solution
> >
> >Hmm. Is this designed to allow custom edit pages based on product
> >type? If it is, it would seem to be an admirable thing to be able
> >to do, and something like that could be ginned into 4.9 (via table-editor,
> >probably). I don't think it could be put into 4.8.
> >
> >--
> >Mike Heins
> >Perusion -- Expert Interchange Consulting
> >phone +1.513.523.7621      <mike@perusion.com>
>
> How would something like that be handled when entering an new record -
> javascript? Seems like it could get messy.
>
> - Ed L.

Not too sure if you quite understand what I am trying to do.  An example is 
probably in order.

In my products table I do not store the retail price, instead the retail price 
(X) is derived from other information such as the price I paid  the supplier 
for the product (A) + the exchange rate for the currency (B) + my margin (C) 
etc.  A, B, C are all values that are stored in the products table, X is 
derived by applying a calculation to A,B and C.

When I edit data from the products table (using item_edit) I want to be able 
to display the sell price (X), but *not* allow the user to edit it (widget 
type=value).  At the same time I want to be able to display A, B and C so 
that the user can edit them and so influence the retail price (X).

In this case we do not need to worry about anything fancy for entering a new 
record as it just works like in the normal case.  I was hoping that I might 
be able to do something like this using mv_metadata.  But from the sounds of 
what Mike is saying, mv_metadata doesen't support anything like this yet.

Might be a good little project for me for 4.9 :-)

Cheers
-- 
David Kelly
CEO / Development Team Leader
Zeald Ltd