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Android Android Data Persistence Migrating a SQLite Database Adding a New Field

Danylo Samotys
Danylo Samotys
9,089 Points
Posted by Danylo Samotys
Danylo Samotys
9,089 Points

Compiler error or some error in challenge code. (bug?)

Can't get it to work. "can't find symbol" error every time (line 33) sqLiteDatabase.execSQL(DB_ALTER);

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:
        sqLiteDatabase.execSQL(DB_ALTER);
    }
  }
}

1 Answer

James Simshaw
James Simshaw
28,738 Points

Hello,

In 

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

you are attempting to execute the execSQL command on the variable sqLiteDatabase, however, the SQLiteDatabase parameter is called database. So if you change that to 

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

You should be able to pass the challenge.

James Simshaw
James Simshaw
28,738 Points

You're welcome. Have fun with Android development.