[QT] test whether QT can connect to the database

First step ： Create a widget project

Then give the project file, that is .pro File to add QT += sql, As shown below ：

The second step ： Use QSqlDatabase

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QSqlDatabase>
#include <QDebug>

namespace Ui {
    
class Widget;
}

class Widget : public QWidget
{
    
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = nullptr);
    ~Widget();

private:
    Ui::Widget *ui;
    QSqlDatabase db;
};

#endif // WIDGET_H

The third step ： Connect to database

#include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    
    ui->setupUi(this);

    db = QSqlDatabase::addDatabase("QMYSQL");
    // Set up ip、 port 、 name 、 password 
    db.setHostName("127.0.0.1");
    db.setPort(3306);
    db.setDatabaseName("mysql");
    db.setUserName("root");
    db.setPassword("root");
    // Open database 
    bool res = db.open();
    if(res){
    
        qDebug()<< "connect success";
    }
    else{
    
        qDebug()<< "connect error";
    }
    // Close the database 
    db.close();

}

Widget::~Widget()
{
    
    delete ui;
}

Step four ： Run the program