应用随附数据库以更新版本时更新SQLite数据库

Question

I am shipping the database file with our android application. For that I followed How to ship an Android application with a database? answered by Danny Remington - OMS .

Now I have to provide the new release In that the database schema has changed, so First I am copying the new db file from assets to data/data directory and writing a insert statement as following in the onUpgrade method of SqliteOpenHelper class:

//rename the old database
new File(DB_PATH + DATABASE_NAME).renameTo(new File(DB_PATH + "DB_old"));
    try 
    {
        //copting new db file from assets to data/data dir
        copyDataBase();
    } 
    catch (IOException e) 
    {
        e.printStackTrace();
    }                       
    SQLiteDatabase DB_old = SQLiteDatabase.openDatabase(DB_PATH + "DB_old", null, SQLiteDatabase.OPEN_READWRITE);
    SQLiteDatabase DB_new = SQLiteDatabase.openDatabase(DB_PATH + "DB_new", null, SQLiteDatabase.OPEN_READWRITE);
    //insert statement from old to new db
    String query = "INSERT INTO DB_new.table1(user_id,user_name) SELECT * FROM DB_old.table1";

    DB_new.execSQL(query);
    DB_old.close();
    DB_new.close();
    //deleting old db file
    new File(DB_PATH + "DB_old").delete();

But the insert statement is throwing a exception android.database.sqlite.SQLiteException: no such table: DB_new.table1

How I can achieve this.Please help me on this.

Answer 1

In your sqlite helper, there is a method onUpgrade which triggers when the version you pass to the super's constructor (of the SqliteOpenHelper ) changes. Thus, you need to change this number, so that onUpgrade fires, then put your code for "re-installing" the database inside this method.