android.database.sqlite.SQLiteException: table X has no column named Y:

I want to create new entry in database . This is my database class:

public class DataBase {

private static final String DATABSE_NAME = "MY_DB";
private static final String DATABSE_TABLE_LOGIN = "tblLogin";
private static final int DATABASE_VERSION = 1;

public static final String DUM="DUM";
public static final String BOOKER_ID = "BookerID";
public static final String BNAME = "BName";
public static final String PASS = "Pass";
String[] Columns_Login = new String[]{DUM,BOOKER_ID,BNAME,PASS};


public static final String DATABASE_CREATE = " CREATE TABLE " + DATABSE_TABLE_LOGIN + " (" +
        DUM + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
        BOOKER_ID+" TEXT NOT NULL, "+
        BNAME + " TEXT NOT NULL, " +
        PASS + " TEXT NOT NULL) " ;


private DatabaseHelper myHelper;

private final Context mycontext;
private SQLiteDatabase myDB;


private static class DatabaseHelper extends SQLiteOpenHelper {

    public DatabaseHelper(Context context) {
        super(context, DATABSE_NAME, null, DATABASE_VERSION);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub

        db.execSQL(DATABASE_CREATE);

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        db.execSQL("DROP TABLE IF EXISTS " + DATABSE_TABLE_LOGIN);
        onCreate(db);
    }

}

public DataBase(Context c) {
    mycontext = c;
}

public DataBase open() throws SQLException {

    myHelper = new DatabaseHelper(mycontext);
    myDB = myHelper.getWritableDatabase();
    return this;
}

public void close() throws SQLException {
    myHelper.close();
}

public long createEntry(String _BID, String _BName, String _Pass) throws SQLException {
    // TODO Auto-generated method stub
    ContentValues cv = new ContentValues();
    cv.put(BOOKER_ID, _BID);
    cv.put(BNAME,_BName);
    cv.put(PASS,_Pass);
    return myDB.insert(DATABSE_TABLE_LOGIN, null, cv);
}

public Boolean CheckLogin(String _BID, String _Pass) throws SQLException{
    Boolean Y_N =false ;
   // Cursor c = myDB.rawQuery("select * from tblLogin where BookerID="+_BID+" and Pass="+_Pass,null);
    Cursor c2 = myDB.query(DATABSE_TABLE_LOGIN, Columns_Login, BOOKER_ID + "=? AND "+ PASS+"=?", new String[]{_BID,_Pass}, null, null, null);

    if(c2.getCount()>0){
        Y_N=true ;
    }
    return Y_N;
}
}

When i call the method CreatEntry() then it gives me the following error:

android.database.sqlite.SQLiteException: table tblLogin has no column named   BookerID: , while compiling: 

Where is the Error ? And also when i call the method CheckLogin it also say that There is no column named BookerID.