Android studio no such column SQL database

alesto :

I do not understand why my note taking application keeps crashing. I click on a button to insert a note that shows in a listView using a SQLite database.

The error given is:

(1) no such column: TITLE
 FATAL EXCEPTION: main
Unable to resume activity: android.database.sqlite.SQLiteException: no such column: TITLE (code 1 SQLITE_ERROR): , while compiling: SELECT ID, TITLE FROM note_table

located here in mainactivity.java:

cursor = database.query(table_name, columns, where, where_args, group_by, having, order_by);

Database:

public class DBOpenHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "notes.db";
public static final String TABLE_NAME = "note_table";
public static final String ID_COLUMN = "ID";
public static final String TITLE_COLUMN = "TITLE";
public static final String TEXT_COLUMN = "ITEM2";
public static final String DATE_COLUMN = "DATE";

SQLiteDatabase db = this.getWritableDatabase();



public DBOpenHelper(Context context) {
    super(context, DATABASE_NAME, null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {
    String createTable = "CREATE TABLE " + TABLE_NAME + " (ID INTEGER PRIMARY KEY AUTOINCREMENT, " +
            " TITLE TEXT)";
    db.execSQL(createTable);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("drop table notes_table");
    onCreate(db);
}

Mainactivity.java:

public class MainActivity extends AppCompatActivity {
private ListView listView;
private ArrayList<String> notes_list;
private ArrayAdapter adapter;
private DBOpenHelper helper;
private SQLiteDatabase database;
private TextView noNotesView;
private Cursor cursor;

@Override
protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    FloatingActionButton fab = findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent(MainActivity.this, Edit_notes.class);
            startActivity(intent);
        }
    });
    noNotesView = findViewById(R.id.empty_notes);

    listView = (ListView) findViewById(R.id.listView);
    notes_list = new ArrayList<>();
    helper = new DBOpenHelper(this);
    database = helper.getWritableDatabase();
}

private void ViewData(){

    String table_name = "note_table";
    String[] columns = {"ID", "TITLE"};
    String where = null;
    String where_args[] = null;
    String group_by = null;
    String having = null;
    String order_by = null;
    cursor = database.query(table_name, columns, where, where_args, group_by, having, order_by); // the error is here

    String total_text = "total number of rows: " + cursor.getCount() + "\n";
    cursor.moveToLast();

    notes_list = new ArrayList<>();
    adapter = new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,notes_list);

    for(int i = 0; i < cursor.getCount(); i++) {
     //   total_text += c.getInt(0) + " " + c.getString(1) + "\n";
        notes_list.add(cursor.getString(1));
        listView.setAdapter(adapter);
        cursor.moveToPrevious();
    }
//    noNotesView.setText(total_text);
}

private void hide_or_show() {
    if (cursor.getCount() == 0) {
        noNotesView.setVisibility(View.VISIBLE);
    } else {
        noNotesView.setVisibility(View.GONE);
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.delete_all) {
        Delete_all();
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
public void onResume()
{
    super.onResume();
    ViewData();
    hide_or_show();
}

public void Delete_all() {
    database.execSQL("delete from " + "note_table");
    adapter.clear();
}

I don't understand why I get this error message since my column name is right. I have tried deleting and recompiling my application without success.

Michael Dodd :

Your problem is with your database class's constructor:

public DBOpenHelper(Context context) {
    super(context, DATABASE_NAME, null, 1);
}

Specifically the 1 in the final argument of super(). That's your database version, and is key to introducing changes to your database structure. You mentioned in your comments that TITLE was previously called ITEM1, on your device it is still called ITEM1 as your app is unaware that the database structure has changed.

You can fix this by introducing a version constant in your class like so:

private static final int DB_VERSION = 2;

And using this variable in your constructor:

public DBOpenHelper(Context context) {
    super(context, DATABASE_NAME, null, DB_VERSION);
}

Whenever you make any structural changes to your database, increment DB_VERSION and this will cause SQLiteOpenHelper to call its onUpgrade() method.