Is this how you have related your three tables?
Orders::__pkOrderID = ItemsOrdered::_fkOrderID
Inventory::__pkInventoryID = ItemsOrdered::_fkInventoryID
Your table occurrence and field names, of course, may differ from mine.
For an explanation of the notation that I am using, see the first post of: Common Forum Relationship and Field Notations Explained
With that set up, a portal to ItemsOrdered can be placed on the Orders layout and a value list listing InventoryID's and a name or description field can be set up to use to select items to be ordered. More sophisticated approaches may also be used, but that's a basic set up that may at least get you started in the right direction.
What kind of criteria might your users use to pull up a found set of records in Inventory? A script can certainly be created that loops through the records found to create matching records in ItemsOrdered that also get the OrderID of the current Order record.
Though the names are different, this is the same basic set up you'll find in the invoices starter solution that came with Filemaker 11 or a similar one that comes with Filemaker 12. You may find it helpful to look at the layouts/scripts/value lists used in those starter solutions.
Thanks PhilModJunk. I had set up the realtionships with more like this
I had hoped to have it so the users search for the name of the chemical, for instance a search for glucose would bring up the glucose entry in teh inventroty and they could then simply selct this to fill out a new order request form.
I will have a go at the solution you suggest and let you know how I go.
Thanks for the help.
You do need to swap around the Items Ordered and Orders tables, but a name based search is indeed possible. Not only can a value list that enters the Inventory ID also display the name of the item so that you can tell that you are selecting 'glucose', but once you have this working, you can adapt the method in the following demo file to get a name based look up system that enters the inventory ID and be able to auto-complete on the value list.
I do, however, observe that your example would appear (to me anyway), to be different from what you specified in your original post. In that, you describe pulling up a found set of records and ordering all of the items in that found set, but your example of what you might want to find in the inventory table sounds much more likely to be a case of finding and adding a single item to the order with each search of your inventory. If you need to find and select individual items, the drop down list methods should work quite well. But if you also want to be able to find an entire group of inventory items and add all of them to your order, that can also be done without changing the basic approach that I have outlined here.
The demo file:
FileMaker 12 users: https://dl.dropbox.com/u/78737945/SimpleNameLookupDemo.fmp12
Pre FileMaker 12 Users: https://dl.dropbox.com/u/78737945/SimpleNameLookupDemo.fp7