mys_qt

Posted 2022-02-03 countryboy666

#ifndef MAINWINDOW_H

#define MAINWINDOW_H

QT       += core gui  sql

#include <QMainWindow>

#include <QtSql>

#include <QVariant>

#include <QDebug>

namespace Ui 

class MainWindow;

class MainWindow : public QMainWindow

    Q_OBJECT

public:

    explicit MainWindow(QWidget *parent = 0);

    ~MainWindow();

private slots:

    void on_listButton_clicked();

    void on_add_clicked();

private:

    Ui::MainWindow *ui;

    //数据库句并

    QSqlDatabase db;

;

#endif // MAINWINDOW_H

#include "mainwindow.h"

#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :

    QMainWindow(parent),

    ui(new Ui::MainWindow)

    ui->setupUi(this);

MainWindow::~MainWindow()

    delete ui;

void MainWindow::on_listButton_clicked()

    this->db = QSqlDatabase::addDatabase("mysql");

    this->db.setHostName("localhost");

    this->db.setUserName("root");

    this->db.setPassword("selen4955");

    this->db.setDatabaseName("student");

    bool ok = db.open();

    if(ok)

    else

        qDebug()<<"error open database because"<<this->db.lastError().text();

    //执行命令

    QSqlQuery query;

    query.exec("select * from student");

   //返回一个结构集

    while(query.next())

        // query.value  是QVariant类型

        int id=query.value(0).toInt();

        QString name=query.value(1).toString();

        qDebug()<<id<<name;

    this->db.close();

void MainWindow::on_add_clicked()

   if(this->db.isOpen())

       qDebug()<<"db is open";

   else

       //错误信息

        qDebug()<<"error open database because"<<this->db.lastError().text();

   this->db = QSqlDatabase::addDatabase("MYSQL");

   this->db.setHostName("localhost");

   this->db.setUserName("root");

   this->db.setPassword("selen4955");

   this->db.setDatabaseName("student");

   bool ok = db.open();

   if(ok)

       QSqlQuery query;

       //先匹配在绑定

             query.prepare("INSERT INTO person (id, name) "

                           "VALUES (:id, :name)");

             query.bindValue(":id",ui->lineEdit->text());

             query.bindValue(":forename", ui->lineEdit_2->text());

             bool ok =query.exec();

             if(ok)

                 qDebug()<<"insert ok";

             else

                 qDebug()<<"insert error";

   else

       qDebug()<<"error open database because"<<this->db.lastError().text();