Table not created in SQLite database android

I am trying to create manually table after one table wallet default created. now when i am trying to create new one table from string table not created. please help me about this. My code is below for database.

public class MyDatabase {
public static final String KEY_ROWID = "_id";
public static final String KEY_DETAIL = "detail";
public static final String KEY_AMOUNT = "amount";
public static final String KEY_DATE = "date";

private static final String DB_NAME = "quickdata";
private static final String DB_TABLE = "Wallet";
private static final String DB_TABLEE = "Wallettw";

private static int DB_VIRSION = 1;

private DBHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;


private static class DBHelper extends SQLiteOpenHelper {

    /* public DBHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
         super(context, name, factory, version);
     }*/

    public DBHelper(Context context) {
        super(context, DB_NAME, null, DB_VIRSION);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE " + DB_TABLE + " (" +
                        KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                        KEY_DETAIL + " TEXT NOT NULL, " +
                        KEY_AMOUNT + " NUMBER NOT NULL, " +
                        KEY_DATE + " TEXT NOT NULL);"
        );

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + DB_TABLE);
        onCreate(db);
    }
}

public MyDatabase(Context c) {
    ourContext = c;
}

public MyDatabase open() {
    ourHelper = new DBHelper(ourContext);
    ourDatabase = ourHelper.getWritableDatabase();
    return this;
}

public void close() {
    ourHelper.close();
}

/////////HEAR I WANT TO CREATE A TABLE IF POSSIBLE/////////////////// public void createCategory(String s)throws SQLException {

    ourDatabase.execSQL("DROP TABLE IF EXISTS "+s);

    ourDatabase.execSQL("CREATE TABLE " + s + " (" +
                    KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                    KEY_DETAIL + " TEXT NOT NULL, " +
                    KEY_AMOUNT + " NUMBER NOT NULL, " +
                    KEY_DATE + " TEXT NOT NULL);"
    );

}

}