Detailed steps for QT to connect to MYSQL database

 //Add MySQL database QSqlDatabase db=QSqlDatabase::addDatabase("QMYSQL"); 
        //Connect to database db.setHostName("127.0.0.1"); //Database server IP
        db.setUserName("root"); //Database username db.setPassword("root"); //Database username and password db.setDatabaseName("sys"); //Database name if(db.open()==false)
        {
            QMessageBox::information(this,"Database open failed",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, '张三', 24,80);");

 q.prepare("insert into student(name, age,score) values(?, ?, ?)"); //? is a placeholder QVariantList name;
   name<<"prime number"<<"waiting"<<"An An";
   QVariantList age;
   age<<-2<<12<<14;
   QVariantList score;
   score<<0<<89<<90;
   //Bind the corresponding values ​​to the fields in order q.addBindValue(name);
   q.addBindValue(age);
   q.addBindValue(score);
   //Execute preprocessing commands q.execBatch();

//Placeholder: + custom name q.prepare("insert into student(name, age,score) values(:n, :a,:s)");
  QVariantList name;
  name<<"Quark"<<"Redmi"<<"Hongmeng";
  QVariantList age;
  age<<5<<10<<3;
  QVariantList score;
  score<<77<<89<<99;
  // Bind the fields in any order because of: + custom name q.bindValue(":n",name);
  q.bindValue(":s",score);
  q.bindValue(":a",age);
  //Execute preprocessing commands q.execBatch();

QSqlQuery q;
        q.exec("update student set score=76 where name='李四'");

QSqlQuery q;
        q.exec("delete from student where name='张三'");

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