问需要在线程中升级SQLite，如何升级，在哪里升级？

EN

public class MySQLiteOpenHelper extends SQLiteOpenHelper {

    protected static final Object lock = new Object();

    private static final int DATABASE_NAME = "mydatabase.db";
    private static final int DATABASE_VERSION = 3;

    private Context context;
    private SQLiteDatabase database;

    public MySQLiteOpenHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);

        this.context = context;
    }

    @Override
    public void onCreate(SQLiteDatabase database) {
        synchronized (lock) {
            this.database = database;

            // Create database statements
        }
    }

    @Override
    public void onUpgrade(SQLiteDatabase database, int oldVersion, int newVersion) {
        synchronized (lock) {
            this.database = database;

            switch (newVersion) {
                case DATABASE_VERSION:
                    switch (oldVersion) {
                        case 1:
                            upgradeFrom1To2();
                        case 2:
                            upgradeFrom2To3();
                    }

                    break;
            }
        }
    }

    private void upgradeFrom1To2() {
        // Upgrade database statements
    }

    private void upgradeFrom2To3() {
        // Upgrade database statements
    }
}