Build Mysql plugin for Qt

[Qt Coder]

My problem is now,


Its showing me MYSQL,MYSQL3 in the list of availabel drivers also allows to connect to database,but as I prepare any query or execute it it gives error "Driver not loaded"





strange behaviour......

[faldzip]

can you show the whole code? because I can't find the place where you create the query object.

[Qt Coder]

QSqlQuery query;
 
   QFile file("d://DB_TRANS.txt");
    file.open(QIODevice::WriteOnly | QIODevice::Text);
    QTextStream out(&file);
 
   QStringList list = QSqlDatabase::drivers();
    QStringList::Iterator it = list.begin();
    while( it != list.end() ) {
        out << (*it) << "\n";
        ++it;
    }
 
     QSqlDatabase  db = QSqlDatabase::addDatabase("QMYSQL");
 
    db.setHostName("192.160.8.153");
    db.setDatabaseName("gaur01");
    db.setUserName("gaur");
    db.setPassword("gaur123");
    db.setPort(3306);
 
      if (!db.open()) {
         out <<"Error\n";
          out << db.lastError().driverText();
        out << "\n";
        out << db.lastError().databaseText();
    }
    else
    {
        out <<"DB open successfully";
        if(query.lastError().type() != QSqlError::NoError)
        {
 
            out << "\nError Occured 1 : " << query.lastError().text();
        }
 
     if(query.prepare("SELECT * FROM temp"))    
             out << "\nQuery prepared successfully : " ;
      else
      {
            out << "\nError in preparing query: "  << query.lastQuery();
            out << query.lastError().text();
      }
 
      if(query.exec())
      {
          out << "\nQuery executed successfully : " ;
            db.commit();
       }     
 
 
        if(query.lastError().type() != QSqlError::NoError)
        {
 
            out << "\nError Occured 2  : " << query.lastError().text();
        }

QSqlQuery query;
    
   QFile file("d://DB_TRANS.txt");
    file.open(QIODevice::WriteOnly | QIODevice::Text);
    QTextStream out(&file);

   QStringList list = QSqlDatabase::drivers();
    QStringList::Iterator it = list.begin();
    while( it != list.end() ) {
        out << (*it) << "\n";
        ++it;
    }

     QSqlDatabase  db = QSqlDatabase::addDatabase("QMYSQL");

    db.setHostName("192.160.8.153");
    db.setDatabaseName("gaur01");
    db.setUserName("gaur");
    db.setPassword("gaur123");
    db.setPort(3306);

      if (!db.open()) {
         out <<"Error\n";
          out << db.lastError().driverText();
        out << "\n";
        out << db.lastError().databaseText();
    }
    else
    {
        out <<"DB open successfully";
        if(query.lastError().type() != QSqlError::NoError)
        {

            out << "\nError Occured 1 : " << query.lastError().text();
        }

     if(query.prepare("SELECT * FROM temp"))    
             out << "\nQuery prepared successfully : " ;
      else
      {
            out << "\nError in preparing query: "  << query.lastQuery();
            out << query.lastError().text();
      }

      if(query.exec())
      {
          out << "\nQuery executed successfully : " ;
            db.commit();
       }     


        if(query.lastError().type() != QSqlError::NoError)
        {

            out << "\nError Occured 2  : " << query.lastError().text();
        }

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the output is

QMYSQL3
QMYSQL
QSQLITE
QODBC3
QODBC
 
DB open successfully
 
Error Occured 1 : Driver not loaded Driver not loaded
 
Error in preparing query: Driver not loaded Driver not loaded
 
Error Occured 2  : Driver not loaded Driver not loaded

QMYSQL3
QMYSQL
QSQLITE
QODBC3
QODBC

DB open successfully

Error Occured 1 : Driver not loaded Driver not loaded

Error in preparing query: Driver not loaded Driver not loaded

Error Occured 2  : Driver not loaded Driver not loaded

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[faldzip]

you are creating query (with a deafault database connection) before creating any databade connection. Try:

QSqlQuery query(db);

QSqlQuery query(db);

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after creating db.