Avoid conflict when adding new field to published app

[Griff]

I have an app that is published and being used by several users. In the past when I have made changes to the underlying data I have had instances where the app crashes with the warning that the number of columns don’t match. That turns into a major exercise, especially for Android users, who sometimes end up having to empty the cache, remove appsheet, reinstall appsheet and reopen the app.

I now have to, once again, add a few columns to some of the data. What is the recommended approach to do this and avoid issues?

[Steve · Accepted solution]

Never add new columns between or before existing ones; only add new columns after existing columns.

When removing columns, only blank them, do not delete them.

This may reduce problems, but may not eliminate them.

[Griff]

Thanks Steve. I was worried that may be the case. I guess I can reduce the risk a little more by adding columns as late as possible and hope someone else still isn’t logged in.

[Griff]

Is there any way I can tell, or keep track of, who is actively logged into the app? If I can be sure all my users are logged off I should be able to safely add fields.

[Steve]

Griff:

Is there any way I can tell, or keep track of, who is actively logged into the app?

Not really. The best you can do is see when someone’s device last exchanged data with the servers.

AppSheet apps are fundamentally distributed apps: the app has its own copy of the data and the user interacts with that local copy. Occasionally, the app syncs with the server. Until and unless the app syncs with the server, you have no visibility into the user’s interaction with the app.

[Griff]

Thanks Steve.

[Lucinda_Mason]

One tip is to add extra columns with names like Temp1,Temp2, etc. Then rename both the column header in the sheet and in the table app definition then regenerate.

The column numbers stay the same, eliminating some of the nasty errors.

[Griff]

Thanks for the suggestion, Lucinda_Mason, however I am unsure what the advantage of using fields named Temp and then renaming them is over using the properly named field in the first place? Can you elaborate? Thanks.