upgrade android app , how to override sqlite

Question

i have a android app of version 4.20 inside 10M sqlitedb, now i have a app of version 4.21 inside 100M sqlitedb,i want upgrade 4.20 to 4.21, when it upgrade have completed, i find the sqlite size still keep 10M in 4.21 app.

so the question is how to override sqlitedb when upgrade app 4.20 -> 4.21 。

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My business is: app will have a lot of data synchronization. In order to optimize, every app will fill in initialization data into SQLite when it is published. Therefore, after each app have upgraded, I hope to completely overwrite SQLite。

any help is very apprecated.

Answer 1

You can upgrade your database version and in the onUpgrade() method of your SQLiteOpenHelper drop all tables and call onCreate() method for recreat database.

public class MyOpenHelper extends SQLiteOpenHelper {

    ...

    private void resetDB(SQLiteDatabase db) {
        
        // Drop all tables 
        db.execSQL("DROP TABLE IF EXISTS table_name");
        // TODO duplicate above line for other tables
        
        // Crate tables again
        onCreate(db);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        resetDB(db);
    }

    @Override
    public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        super.onDowngrade(db, oldVersion, newVersion);
        resetDB(db);
    }
}