Qt学生成绩管理系统登录按钮连接到数据库

实现当点击登录界面的登录按钮时，会连接到本地MySQL数据库，根据相应数据表实现登录。


login1.pro

#
# Project created by QtCreator 2022-01-06T22:10:15
#
#-------------------------------------------------QT += core gui sqlgreaterThan(QT_MAJOR_VERSION, 4): QT += widgetsTARGET = login1
TEMPLATE = app# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0SOURCES += main.cpp\mainwindow.cpp \logindialog.cppHEADERS += mainwindow.h \logindialog.h

logindialog.h

#ifndef LOGINDIALOG_H
#define LOGINDIALOG_H#include
#include
#include
#include
#include
#include
#include class LoginDialog : public QDialog
{Q_OBJECT
public:LoginDialog(QWidget *parent = 0);~LoginDialog();private:QLabel *usrLabel;QLabel *pwdLabel;QLineEdit *usrLineEdit;QLineEdit *pwdLineEdit;QPushButton *LoginBtn;QPushButton *exitBtn;private slots:void login();void close();signals:void signal_username(QString);};#endif // LOGINDIALOG_H

logindialog.cpp

关键代码（连接部分）

void LoginDialog::login(){QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");db.setHostName("localhost");db.setDatabaseName("scts"); //连接的数据库名字db.setUserName("root");db.setPassword("qazqaz12");if(!db.open()) //通过open连接数据库qDebug()<<"连接失败";else qDebug()<<"连接成功";QString zhanghao = usrLineEdit->text(); //zhanghao和mima是sql中对应表的列名QString mima = pwdLineEdit->text();QString s=QString("select * from guanli where zhanghao=&＃39;%1&＃39;and mima=&＃39;%2&＃39; ").arg(zhanghao).arg(mima);QSqlQuery query(db); //数据库函数的传参query.exec(s);if(query.first()){QMessageBox::information(NULL, "登陆成功", "登陆成功！！！", QMessageBox::Yes);accept();}elseQMessageBox::warning(NULL,"Error","登录失败，请重试！！！");usrLineEdit->clear();pwdLineEdit->clear();usrLineEdit->setFocus();}


main.cpp

#include "mainwindow.h"
#include
#include "logindialog.h"int main(int argc, char *argv[])
{QApplication a(argc, argv);MainWindow w;LoginDialog dlg;if(dlg.exec()==QDialog::Accepted){w.show();}return a.exec();
}