I am currently working on Zoho Creator to set-up a database for product samples.

I have 2 app. Both with only one form and one view.

The first app is to create new samples from a form (Create_Sample) or view/modify/delete them from a view (View/Modify_Sample)

Sometimes, we need to pack several samples in one box (to send them to another place for example)

So I have a second app in order to create a new box from a form (Create_Box) or view/modify/delete these boxes from a view (View/Modify_Box).

I have managed to use a lookup field with bidirectional link in the Box form.

This enable the creator of a box to view the available items from the "sample application" and select one or mutliple items to pack them in a box.

This will also allow in the "Sample view" to know if an item belong to a box.

Now my concern:

I have a "Location" in my "Sample App" to know where are the samples (required field when creating Sample)

I have a "Box_Location" in my "Box App" to know where are the boxes (required field when creating Box)

I want that if somebody creates a box or modify a "Box_Location", automatically, the items within the box will have a updated "Location" (in the "Sample App").

NB: 

- Both "Sample locations" and "Box Location" fields are dropdown box (with same info)-

- Both are required fields so that a box location must update an existing sample location anyway

- If a box is deleted, I want the last know box location to remain as Sample location

I have tried to do something with the lookup field again but not working

I have tried to use the "fetch and update" script but I am very bad at script

I noticed that we can't use scripts to update another App and that I might have to use a "Function"

Is there any workaround to my problem?

If not, what should look like the function in the sample App and the script in the Box App?

Will it be working because of the dropdown box?

Thanks in advance