Conditional Ref

[davidPaiva]

It would be a great addition if we had a column type called conditional ref, it's need to be a different column because it would add a process that can make the app slower.
The concept here is the ref table on a ref column would be selected based on a condition.
At the moment, if we have a column that could have values from 4 different tables we need to create columns 4 additional columns. If for some reason we need to expand to a 5th table source for the ref we need to change the structure to add another additional column

[Marc_Dillon]

I don't understand this at all.

[davidPaiva]

A ref can make reference to one, and only one, table.
Sometimes, we need a column that can receive data from different tables depending on the result of a condition.
Ex: You have an app that controls the lobby.  You have a column that is a ref to a person that enter in the lobby, but you have two tables: visitors and employees.
At the moment, you would need to have two different columns one with the ref to visitors and another with the ref to employees, then you would need to do something (like a selector) to decide which will be the correct column.
My suggestion is that the conditional ref will first check the condition and then get the ref list based on the results of the condition.
I am on my second app in app sheet and in both apps I had this issue (needed to create columns for each different ref even if I would use only one of those columns)

[Marc_Dillon]

What you are referring to is called "polymorphic association". I highly suggest you look this up and read on the subject.

Polymorphic association is generally considered as bad/un-standard/un-normalized in the relational database realm, which Appsheet is based on. So I suspect that there's almost no chance you'll get this feature request fulfilled.

[RedVox]

I agree with Marc.  Perhaps the example problem is better solved by having a people table where a person can be an employee or a visitor.