Gerhardus,

> My problem is I have a invoice table and in invoice items table.
> The customer want to be able to give discount on the total invoice and per
> item. In the invoice items table he wants to see what the profit margin is.

First off, you don't necessarily have to structure your data base
according to what your customer wants to *see*, as a general rule.

> To do this I need to know the value of the discount in the invoice table
> which is the master. Can this be done in a calculated field or how do you
> suggest I do it.

Use a regular field and keep it in sync with a couple of triggers
(before insert, before update).
Ciao
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