How to perform a lightweight migration on sqlite database in Android just the way like iOS?

Question

I want to add some keys, such as "URL", to the existed table.

In iOS, I can create a new version of data model and perform a light weight migration.

However, the default way in SQLiteOpenHelper seems to destroy the old DB and create a new one.

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // Drop older table if existed
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_1 + ", "
            + TABLE_2 + ", " + TABLE_3 + ", "
            + TABLE_4);
    // Create tables again
    onCreate(db);
}

How can I keep the old database and just add some new keys in Android?

Answer 1

You can write your own Upgrade sql query to upgrade your database.

Call onCreate after droping all tables is just a easy way to upgrade tables without caring about FKs, null fields or database version.

Use oldVersion and newVersion to make the correct changes (alter table) on your database.

onUpgrade doc