[Qt-interest] QSqlDatabase

[Riccardo Roasio]

Hi,

i have a probelm with a QSqlDatabase object, it gives me this warning :

QSqlDatabasePrivate::addDatabase: duplicate connection name
'qt_sql_default_connection', old connection removed.

How can i solve this issue?

The class that use the QSqlDatabase object is this one:

#ifndef MYSQLCONNECTION_H
#define MYSQLCONNECTION_H

#include <QtSql>
#include <QString>
#include <QCoreApplication>
#include <QSqlDatabase>
#include <QSqlError>
#include <QStringList>
#include <QtDebug>
#include <iostream>

#include "logger.h"

class MysqlConnection
{

public:
    MysqlConnection(QString host,QString database,QString
username,QString password);
    void close();
    QSqlQuery query(QString q);
    bool opened();

private:
    QString username;
    QString password;
    QString database;
    QString host;
    QString connection;
    QSqlDatabase db;
    bool op;

    Logger *logger;
};

#endif // MYSQLCONNECTION_H


#include "mysqlconnection.h"

MysqlConnection::MysqlConnection(QString h,QString d,QString u,QString p)
{
    std::cout<<"1"<<std::endl;
   logger=new Logger();

   logger->logOnFile(" MysqlConnection","MysqlConnection","Opening
connection.");

   host=h;
   database=d;
   username=u;
   password=p;

   logger->logOnFile(" MysqlConnection","MysqlConnection","Adding database.");
   db = QSqlDatabase::addDatabase("QMYSQL");
   logger->logOnFile(" MysqlConnection","MysqlConnection","Database added.");
   db.setHostName("localhost");
   db.setDatabaseName("osty");
   db.setUserName("root");
   db.setPassword("root");
   logger->logOnFile(" MysqlConnection","MysqlConnection","Connecting
to database.");
   op=db.open();
   logger->logOnFile(" MysqlConnection","MysqlConnection","Connected.");
   connection=db.connectionName();
   logger->logOnFile(" MysqlConnection","MysqlConnection","Connection
name |"+connection+"|.");

   logger->logOnFile(" MysqlConnection","MysqlConnection","Connection opened.");
   std::cout<<"2"<<std::endl;
}


QSqlQuery MysqlConnection::query(QString q)
{
    std::cout<<"3"<<std::endl;
    logger->logOnFile(" MysqlConnection","query","Executing query.");

   QSqlQuery query_result;

   if(op)
   {
     logger->logOnFile(" MysqlConnection","query","Executing...");
     query_result=QSqlQuery(db);
     query_result.exec(q);
     logger->logOnFile(" MysqlConnection","query","Executed.");
   }
   else
   {
       logger->logOnFile(" MysqlConnection","query","Query not
executed. Db not opened.");
   }
   std::cout<<"4"<<std::endl;
   return query_result;
}

void MysqlConnection::close()
{
    std::cout<<"5"<<std::endl;
    logger->logOnFile(" MysqlConnection","close","Closing connection.");
    db.close();
    if(op)
    {
      op=false;
 //     db.removeDatabase(connection);
    }
    db.~QSqlDatabase();
    logger->logOnFile(" MysqlConnection","close","Connection closed.");
    std::cout<<"6"<<std::endl;
}

bool MysqlConnection::opened()
{
    return op;
}