Apologies in advance from a newbie... for a (probably) basic question...
How does an invoicing system work, wherein an invoice file references perhaps a few, or perhaps many, inventory items? You don't want a third file to list the items, which would be redundant. You don't want a large number of fields in the invoice file, just in case a large number of items are bought... that would be wasteful of space. You'd want to set up a relationship from the invoice file to the inventory (or product) file, and have the items listed in a portal... but how to set up the relationship for a highly variable number of such items?
(What I want to do isn't really an invoicing system, but is comparable... it's a field trip "card" which would have a file with records for field trips, and should list the students who are going on each one, names drawn from a student file of maybe 200 or so names).
If the answer is simple... apologies and thanks. If it complicated, then perhaps someone could direct me to a discussion of the technique involved.