Modifying the data model and update App Service

[blmiles]

I have added a couple fields to a data class in the Maui.App and then the same in the App Service code.

To affect these changes in the deployed Azure App Service, underlying EF and the the Azure db itself...
Do I need to add any scripting or other instructions to affect those changes OR is it simply a redeploy of the App Service via azd CLI?

@adrianhall, sorry to bug... any advice on this before I break stuff :)

Thanks

[adrianhall]

As with all EF related changes, you will need to do migrations on both the client and the server.

In general, when in production, you have to be very careful about adding properties to ensure clients that have not yet upgraded don’t get broken. I generally add an API with a “dbVersionDate” and populate that from the date my schema changed. Then, in my client startup, I call the server API to get the dbVersionDate and if it is different to what I have, I tell the user to update before continuing. This way the client is in sync with the server.

The problem occurs when the client is long-lived (e.g. iOS) and users don’t generally quit. you still have to trap errors.

[blmiles]

OK, so reran the azd up, worked just fine.
Rebuilt client App after deleting bin and obj. All good.

iOS client and App Service all sync perfectly including data in new fields. So client and service are fine.
UWP app complains about one of the new fields missing when sync'ing. Something not cleared out in UWP client.

This is my first UWP app, only built iOS and Android up to now, so I don't know where else VS might leave remnants of a previously built app anywhere on the dev machine. Not quite sure right now how to clean up the UWP app. Same code base as the iOS app.

Any insights? anyone?

Once I solve this I can run full tests and look toward production. It's almost done!
THEN will look at migrations... as some added features are planned for later.

[adrianhall]

I’m suspecting your SQLite database has not been cleared. Where are you storing it? When storing data on Windows, I normally am explicit about where it is stored. It’s probably in the AppData folder for the application if you haven’t specified a path.

Info on storage of data in UWP: https://learn.microsoft.com/en-us/windows/apps/design/app-settings/store-and-retrieve-app-data

[blmiles]

Hi Adrian,

In my code, the db path is determined with this:

Uses the Microsoft.Maui.Storage.FileSystem

string applicationPath = FileSystem.AppDataDirectory;

Then I concat the db name and set the connection:

SqliteConnection dbConnection = new SqliteConnection("Data Source=" + dbPath + "; Cache=Shared");
And you're right, I did not clear that. Fixed!

This is also remnant of all code before I added the UWP platform.
Thanks for the link.

[adrianhall]

So you can just log your SqliteConnection string and it will tell you the directory.

[blmiles]

Yep, should have thought to check that anyway.
All platforms working now. Local db and sync'ing.

Came across another issue related to Settings and IPreferences field length (strings) and it's only an issue in UWP.
iOS and Android seem unaffected but UWP complains. But that's for a different discussion in the Maui community if I cannot resolve it...

Thanks again Adrian, I'll be looking into migrations to avoid all these EF update difficulties going forward.