QR code Assitance

AppSheet AppSheet Q&A
1

I’m developing an app. These images show my database. What you will find there is a sheet called “People” where is the registration of people and the generation of a qr code to give attendance to an event to people. As second sheet you will find “Attendance” where it is related to a form that reads with the section “Code” the QR of the person and in name and dni has a lookup to the table “People”.

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The main problem of my app is that I need the code to be read only once, that can be registered once that qr code has been read by the application and that 2 different people can not use the same qr code so I avoid people who can sneak. I need a solution for me to implement in the app fundamentally to be automatic registration that the qr code and that person has already entered the enclosure.

2

The question is what is unique about each QR Code?

I will assume it is the DNI number. All you need to do is identify that the DNI number has been recorded in the Assistencia table. You can do this is two ways:

  1. On save of the Assistencia Form, execute an action that updates the [Use?] column to TRUE for the Person row that has that DNI number.
  2. Move the [Use?] column to a virtual column and set it with an expression that checks if the DNI number exists in the Assistencia table.

Using a Virtual Column in this case will likely not have much impact on performance so it should be ok.

I hope this helps!