QT MYSQL 데이터베이스 연결 상세 절차

 //  mysql    
        QSqlDatabase db=QSqlDatabase::addDatabase("QMYSQL"); 
        //     
        db.setHostName("127.0.0.1");//      IP
        db.setUserName("root");  //      
        db.setPassword("root");//        
        db.setDatabaseName("sys"); //    
        if(db.open()==false)
        {
            QMessageBox::information(this,"       ",db.lastError().text());
            return;
        }

QSqlQuery q;
q.exec("create table student(id int primary key auto_increment, name varchar(255), age int, score int)ENGINE=INNODB;");

q.exec("insert into student(id, name, age,score) values(1, '  ', 24,80);");

 q.prepare("insert into student(name, age,score) values(?, ?, ?)");  //?    
   QVariantList name;
   name<<"  "<<"  "<<"  ";
   QVariantList age;
   age<<-2<<12<<14;
   QVariantList score;
   score<<0<<89<<90;
   //               
   q.addBindValue(name);
   q.addBindValue(age);
   q.addBindValue(score);
   //       
   q.execBatch();

//    :+     
  q.prepare("insert into student(name, age,score) values(:n, :a,:s)");
  QVariantList name;
  name<<"  "<<"  "<<"  ";
  QVariantList age;
  age<<5<<10<<3;
  QVariantList score;
  score<<77<<89<<99;
  //              :+     
  q.bindValue(":n",name);
  q.bindValue(":s",score);
  q.bindValue(":a",age);
  //       
  q.execBatch();

QSqlQuery q;
        q.exec("update student set score=76 where name='  '");

QSqlQuery q;
        q.exec("delete from student  where name='  '");

QSqlQuery q;
    q.exec("select *from student");
    while(q.next())   //    false
    {
        //   
        //qDebug()<<q.value(0).toInt()<<q.value(1).toString()<<q.value(2).toInt() 
        <<q.value(3).toInt();
        //   
        qDebug()<<q.value("id").toInt()<<q.value("name").toString()<<q.value("age").toInt() 
        <<q.value("score").toInt();
    }