I am trying to make an app for lending products, in a list the date and time for lending and receiving back are stored. now I want to enter a check that checks whether the chosen date is not already planned in a previous order.
What I came up with to make this work is to create a hidden screen that does the check. in the hidden screen there is a gallery of all orders, if I check out for each gallery item whether this date overlaps with itself, and if so, does that gallery item pass its ID. by reading the ID again, it is immediately possible to indicate why the chosen date is unsuitable, because it then overlaps with ID.. with date...
This must be a cumbersome way, but I can't even get this to work, what formula should I use for the gallery items to do this check?
or is there a better, simpler or faster way to do this check?
example of the hidden screen:
