升级时使用新版本的数据库错误

Question

I am adding a column to a DB in the onUpgrade() method which works fine on devices / emulators where the previous DB version exists.

However when installing on devices for first time I get an error starting the column (in on upgrade()) can't be found.

I am assuming this is because the device can't find a previous version so the onUpgrade() is not executed.

Is there a way around this?

Cheers

Here is the code:

@Override 
    public void onCreate(SQLiteDatabase db) {
        // only called once when DB first created, takes DB as arg
        db.execSQL("CREATE TABLE "+ DATABASE_TABLE + " ("+
        KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
        KEY_DIVELOCATION + " TEXT , "+ 
        KEY_DIVESITE + " TEXT , " +
        KEY__DIVENUMBER + " INTEGER DEFAULT 0 , " +
        KEY__DIVEDATE + " TEXT , " +
        KEY_DIVERATING + " FLOAT DEFAULT 0.0 , " +
        KEY_BOTTOMTIME + " INTEGER DEFAULT 0 , " +
        KEY_DIVEBUDDY + " TEXT , " +
        KEY__DIVECENTER + " TEXT , " +
        KEY_ENDBAR + " INTEGER DEFAULT 0 , " +
        KEY_STARTBAR + " INTEGER DEFAULT 0 , " +
        KEY_VIZIBILTY + " INTEGER DEFAULT 0 , " +
        KEY_WATERTEMP + " INTEGER DEFAULT 0, " +
        KEY_COMMENTS + " TEXT , " +
        KEY_CONDITIONS + " TEXT , " +
        KEY_DIVEPICTURE + " TEXT );"
        );
        //use for dtabase querys
        columns = new String[]{KEY_ROWID, KEY_DIVERATING, KEY_BOTTOMTIME, KEY_DIVEBUDDY, 
                KEY__DIVECENTER, KEY_DIVELOCATION,
                KEY__DIVENUMBER, KEY_DIVESITE, KEY_ENDBAR, KEY_STARTBAR, 
                KEY_VIZIBILTY, KEY_WATERTEMP,KEY__DIVEDATE, 
                KEY_COMMENTS, KEY_CONDITIONS, KEY_DIVEPICTURE};



    }//end onCreate DB inner helper class

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // if table exits, drop it (delete) and recreate it to upgrade it
        db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
        onCreate(db);
        //need to call upgrade and add a int column for depth, newVersion is 2
        if (newVersion> oldVersion ){
            db.execSQL("ALTER TABLE "+DATABASE_TABLE+" ADD COLUMN "+KEY_DEPTH+" INTEGER DEFAULT 0");
        }

Answer 1

onUpgrade will be only called when a version of database will gets old. ie you change the version which you passes during database creation.

eg

super(context, DATABASE_NAME, null,DATABASE_VERSION);

Now if DATABASE_VERSION is changed, only then onUpgrade will gets called...

So i think, you just need to execute your create table commands in onCreate and only use commands of changing tables in onUpgrade . That way you won't have this issue.

Hope it helps