基于qt和mysql的学生注册系统（二）

接下来是connection.h头文件，主要用于建立数据库连接：
p, li { white-space: pre-wrap; }

p, li { white-space: pre-wrap; }    [code]#ifndef CONNECTION_H

#define CONNECTION_H

#include <QMessageBox>

#include <QSqlDatabase>

#include <QSqlQuery>

#include <QtSql>

#include <QVector>

#include <QString>

#include <mainwindow.h>

static bool createConnection()

{

QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");

db.setHostName("localhost");

db.setDatabaseName("Enroll");

db.setUserName("root");

db.setPassword("1");

qDebug() <<"hell";

if(!db.open())

{

QMessageBox::critical(0, qApp->tr("Cannot open database"),

qApp->tr("Unable to establish a database connection."

), QMessageBox::Cancel);

return false;

}

// test the connection

QSqlQuery query;

query.exec("SELECT a FROM Student");

qDebug() <<query.size();

while(query.next())

{

QString id = query.value(0).toString();

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

QString data = query.value(2).toString();

qDebug() << id << ", " << type << ", " << data <<endl;

     qDebug() <<query.size();

}

}

#endif // CONNECTION_H

然后是login类：[/code]

我的做法是从对话框读取用户名和密码，用于登录数据库。

头文件：

p, li { white-space: pre-wrap; }    [code]#ifndef LOGIN_H

#define LOGIN_H

#include <QWidget>

#include <QLineEdit>

#include <QLabel>

#include <QDialogButtonBox>

#include <QGridLayout>

#include <QDialog>

#include <QMessageBox>

class login : public QDialog

{

Q_OBJECT

public:

explicit login(QWidget *parent = 0);

signals:

public slots:

void accept();

private:

QLineEdit *usrEdit;

QLineEdit *pwdEdit;

QLabel *usrLabel;

QLabel *pwdLabel;

QDialogButtonBox *buttonBox;

QGridLayout *grid;

};

#endif // LOGIN_H

cpp文件：

[/code]

p, li { white-space: pre-wrap; }    [code]#include "login.h"

login::login(QWidget *parent) :

QDialog(parent)

{

this->usrLabel=new QLabel(tr("UserName:"));

this->pwdLabel=new QLabel(tr("PassWord:"));

this->usrEdit=new QLineEdit;

this->pwdEdit=new QLineEdit;

pwdEdit->setEchoMode(QLineEdit::Password);

this->buttonBox= new QDialogButtonBox(QDialogButtonBox::Ok

| QDialogButtonBox::Cancel);

connect(buttonBox, SIGNAL(accepted()), this, SLOT(accept()));

connect(buttonBox, SIGNAL(rejected()), this, SLOT(reject()));

grid=new QGridLayout;

grid->addWidget(usrLabel,0,0);

grid->addWidget(usrEdit,0,1);

grid->addWidget(pwdLabel,1,0);

grid->addWidget(pwdEdit,1,1);

grid->addWidget(buttonBox,2,1);

this->setWindowTitle("Login");

resize(100,200);

this->setLayout(grid);

}

void login::accept()

{

if(usrEdit->text()=="root"&&pwdEdit->text()=="1")

{

QDialog::accept();

}

else

{

QMessageBox::warning(this,tr("Warning"),tr("Error"),QMessageBox::Yes);

usrEdit->clear();

pwdEdit->clear();

usrEdit->setFocus();

}

}

下篇文章贴关于实现sql语句的几个类。

[/code]