Question

When my app is created, my database is copied from the assets folder to my app.

Now if i want to do an onUpgrade, i just want to overwrite all Tables EXCEPT of one.

But how can i do this?
I just can write the whole database or nothing…

Please help me with this.

This doesnt work of course, because it doesnt overwrite the existing tables, it just backups the one i do not replace..

public void createDataBase() throws IOException{
        boolean dbExist = checkDataBase();
        if(dbExist){   
            myDataBase = this.getWritableDatabase();
        } else {
            myDataBase = this.getReadableDatabase(); 
            try { 
                copyDataBase(); 
            } catch (IOException e) { 
                throw new Error("Error copying database"); 
            }
        }       
    }
private void copyDataBase() throws IOException{

        //Open your local db as the input stream
        InputStream myInput = myContext.getAssets().open(DB_NAME);

        // Path to the just created empty db
        String outFileName = DB_PATH + DB_NAME;

        //Open the empty db as the output stream
        OutputStream myOutput = new FileOutputStream(outFileName);

        //transfer bytes from the inputfile to the outputfile
        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer))>0){
            myOutput.write(buffer, 0, length);
        }

        //Close the streams
        myOutput.flush();
        myOutput.close();
        myInput.close();

    }
@Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.i("onUpgrade", "newVersion: "+newVersion+", oldVersion: "+oldVersion);
        try{
        if(newVersion > oldVersion){
            db.execSQL("ALTER TABLE Results RENAME TO temp_Results");
            db.execSQL("CREATE TABLE Results (lektionenId INTEGER PRIMARY KEY, testPassed Integer, lektionPassed Integer)");
            db.execSQL("INSERT INTO Results (testPassed, lektionPassed) SELECT testPassed, lektionPassed FROM temp_Results");
            db.execSQL("DROP TABLE IF EXISTS temp_Results");
        }
        } catch(Exception e){
            Log.i("exc", ""+e);
        }
    }

EDIT:

Where i call the Database:

myDbHelper = new LernAppOpenHelper(this, "LernApp", DbConfig.DB_VERSION_LERNAPP);       

        try {
            String[] columns = {"_id","description"};
            myDbHelper.createDataBase();
            myDbHelper.openDataBase();

            cursor = myDbHelper.getQuery("Uebersicht", columns, null, null, null, null, null);

And my onUpgrade Method:

@Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        if(newVersion > oldVersion){
            if("LernApp".equals(DATABASE_NAME)){
                myContext.deleteDatabase(DATABASE_NAME);
                try { 
                    copyDataBase(); 
                } catch (IOException e) { 
                    throw new Error("Error copying database"); 
                }
            }

        }

    }

Answer 1

Step #1: Copy your table data from the old database into memory.

Step #2: Restore your database from your copy in assets.

Step #3: Update your new database from the table data in memory.

If the table might be too big for that, copy the data to a file and then back from a file.

---

EDIT

Or:

Step #1: Copy your old database (the one being replaced) to a new database using standard Java file I/O.

Step #2: Restore your database from your copy in assets.

Step #3: Open both databases.

Step #4: Load the table you are keeping from the old database and pour its contents into the new database. Be sure to watch your transactions: the default of one-transaction-per-statement can make this sort of work very slow.

Step #5: When done, close the old database and delete it.