Updating SQLite database when releasing new version of the android app on the store

Question

I'm using sqlite in my android app, my database file is called data.db. Let's suppose that I have two table in it one is having static values(read only) and second is saves dynamic values and pushed the app to the playStore.

In the next version I updated the data.db and I updated the values in first table, added new columns in second table and added third new table and push the app to the PlayStore. So how I can check if user is updating the app and what is best possible way to save existing data and how I can update data.db programmatically when it is a update not a fresh install?

Answer 1

You can use SQLiteOpenHelper's onUpgrade method. In the onUpgrade method, you get the oldVersion as one of the parameters.

In the onUpgrade use Switch case and in each of the cases use the version number to keep track of the current version of Database that was sent for each new Version of Database.

Its best that you loop over from oldVersion to newVersion, incrementing version by 1 at a time and then upgrade the database stepbystep. This is very helpful when someone with Database version 1 upgrades the app after a long time, to a version using database version 7 and the app starts crashing because of certain incompatible changes.

Then the updates in database will be done stepwise, covering all possible cases i.e incorporating the changes in the database done for each new version and thereby preventing your application from Crashing.

Answer 2

There are two ways

1] Changed database version so that when user updates an app SQLiteOpenHelper's onUpgrade() method gets executed in this method you can write a code to drop tables n create new tables according to new schema and send network calls to fetch data.

2] Push app with pre-installed db. Create database with db version and save it in assets folder. Whenever app runs compare versions of assets's db & app's db. if asset's db version is higher than app's db then this means you need to update database. Directly copy Assete's db into folder structor and sends delta call to fetch data.