Where am I getting it wrong? Execute the appropriate statement in the onUpgrade() method on AlienSQLiteHelper.java

public class AlienSQLiteHelper extends SQLiteOpenHelper {

  public static final String DB_NAME = "aliens.db";
  public static final int DB_VERSION = 2;

  public static final String ALIENS_TABLE = "ALIENS";
  public static final String COLUMN_NAME = "NAME";
  public static final String COLUMN_TYPE = "TYPE";
  public static final String COLUMN_HOME_PLANET = "HOME_PLANET";

   public static final String CREATE_ALIENS = "CREATE TABLE " + ALIENS_TABLE + " (" +
          "_id INTEGER PRIMARY KEY AUTOINCREMENT," +
          COLUMN_NAME + " TEXT, " +
          COLUMN_TYPE + " TEXT," +
    COLUMN_HOME_PLANET + "TEXT)";

 public static final String DB_ALTER = "ALTER TABLE " + ALIENS_TABLE + " ADD COLUMN " + COLUMN_HOME_PLANET + " TEXT ";

  public AlienSQLiteHelper(Context context) {
    super(context, DB_NAME, null, DB_VERSION);
  }

  @Override
  public void onCreate(SQLiteDatabase sqLiteDatabase) {
    sqLiteDatabase.execSQL(CREATE_ALIENS);
  }

  @Override
  public void onUpgrade(SQLiteDatabase database, int oldVersion, int newVersion) {
   switch (oldVersion) {
     case 1:
     database.execSQL(DB_ALTER); }

    //switch (oldVersion) { case 1: database.execSQL(DB_ALTER); }

    }
  }
}