第十七章电子商城系统

一、功能需求分析

1、登录功能

用户需要输入用户名和口令登录商城系统，口令用密码形式保护，口令不正确重新输入。

界面主要用label、LineEdit、pushbutton等控件组成

2、商城系统功能

实现新的产品的入库，卖完和不卖的产品的清仓，并对数据库中的商品的库存、进价、售价、名称、类别和样品照片的显示。

 界面主要用label、LineEdit、pushbutton和TableView等控件组成

提供预售商品功能，可以选择商品类别、名称、数量、库存、售价并计算总共金额。

界面主要用label、LineEdit、pushbutton和 ListWidget等控件组成

二、开发环境

win10+QT5.9_MinGW+MySQL5.7

三、实现细节

1、工程结构

2、登录功能实现

全部实现代码在logindialog类中，继承Qdialog

主要函数包括登录按钮单击事件和退出登录事件

登录按钮单击事件：通过用户名查询数据库中的口令，再与口令框中的口令进行比较，相同验证通过，不相同弹出消息框提示失败，重新输入口令

退出登录事件：直接调用QDialog::reject()函数，退出登录界面。

logindialog.h

#ifndef LOGINDIALOG_H

#define LOGINDIALOG_H

#include <QDialog>

#include <QSqlQuery>

#include <QMessageBox>

#include <QCryptographicHash>

namespace Ui {

class LoginDialog;

}

class LoginDialog : public QDialog

{

Q_OBJECT

public:

explicit LoginDialog(QWidget *parent = 0);

~LoginDialog();

QString strToMd5(QString str);

private slots:

void on_loginPushButton_clicked();

void on_exitPushButton_clicked();

private:

Ui::LoginDialog *ui;

};

#endif

logindialog.cpp

#include "logindialog.h"

#include "ui_logindialog.h"

LoginDialog::LoginDialog(QWidget *parent) :

QDialog(parent),

ui(new Ui::LoginDialog)

{

ui->setupUi(this);

setFixedSize(400,300); //登录对话框固定大小

ui->pwdLineEdit->setFocus(); //口令框置焦点

}

LoginDialog::~LoginDialog()

{

delete ui;

}

void LoginDialog::on_loginPushButton_clicked()

{

if(!ui->pwdLineEdit->text().isEmpty())

{

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

d.setHostName("localhost");

d.setDatabaseName("emarket");

d.setUserName("root");

d.setPassword("123456");

bool ok = d.open();

if(!ok)

{

QMessageBox::critical(0,QObject::tr("数据库连接失败"),"无法创建连接！请检查排除故障后重启程序。",QMessageBox::Cancel);

}

QSqlQuery query(d);

QString admin = ui->adminLineEdit->text();

query.exec("select PassWord from member where MemberID='" + admin + "'");//从数据库中查询出口令密码字段

query.next();

QString pwdMd5 = ui->pwdLineEdit->text();

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

if( pwd == pwdMd5)

{

QDialog::accept();//验证通过

}

else

{

QMessageBox::warning(this,tr("口令错误"),tr("请输入正确的口令！"),QMessageBox::Ok);

ui->pwdLineEdit->clear();

ui->pwdLineEdit->setFocus();

}

}

else

{

ui->pwdLineEdit->setFocus();

}

}

void LoginDialog::on_exitPushButton_clicked()

{

QDialog::reject();//退出登录框

}

QString LoginDialog::strToMd5(QString str)

{

QString strMd5;

QByteArray qba;

qba = QCryptographicHash::hash(str.toLatin1(),QCryptographicHash::Md5);

strMd5.append(qba.toHex());

return strMd5;

}

3、商城系统功能实现

商城系统功能在mainwindow类中实现

对界面显示的信息进行初始化

将新品入库页显示在前

将商品类别导入到下拉框选项中

void MainWindow::initMainWindow()

{

ui->stackedWidget->setCurrentIndex(1);

ui->toolBox->setCurrentIndex(0);

QSqlQueryModel *categoryModel = new QSqlQueryModel(this);//商品类别模型数据

categoryModel->setQuery("select Name from category");

ui->newCategoryComboBox->setModel(categoryModel);//商品类别列表加载（新品入库页）

commodity_model = new QSqlTableModel(this);//商品信息视图

commodity_model->setTable("commodity_inf");

commodity_model->select();

ui->commodityTableView->setModel(commodity_model);//库存商品记录数据网格信息加载（新品入库页）

ui->preCategoryComboBox->setModel(categoryModel);//商品类别列表加载（预售订单页）

loadPreCommodity();//在预售订单页加载商品信息

myMemberID = "b02020622";

//myOrdered = false;

myOrdered = true;

//myOrderID = 0;

myOrderID = 4;

myPaySum = 0;

QListWidgetItem *title = new QListWidgetItem;

title->setText(QString("当 前 订 单 【 编号 %1 】").arg(myOrderID));

title->setTextAlignment(Qt::AlignCenter);

//ui->sellListWidget->addItem(title);

}

入库操作

//入库操作

void MainWindow::on_newPutinStorePushButton_clicked()

{

QSqlQuery query;

query.exec(QString("select CategoryID from category where Name='%1'").

arg(ui->newCategoryComboBox->currentText()));//根据类别名查询类别ID

query.next();

int categoryid = query.value(0).toInt();//将要入库的商品类别

QString name = ui->newNameLineEdit->text();//商品名称

float inputprice = ui->newInputPriceLineEdit->text().toFloat();//进价

float outputprice = ui->newOutputPriceLineEdit->text().toFloat();//售价

int count = ui->newCountSpinBox->value();//入库量

query.exec(QString("insert into commodity(CategoryID, Name, Picture, InputPrice, OutputPrice, Amount) values(%1, '%2', NULL, %3, %4, %5)").

arg(categoryid).arg(name).arg(inputprice).arg(outputprice).arg(count));//插入新入库的商品记录

//插入照片

QByteArray picdata;

QBuffer buffer(&picdata);

buffer.open(QIODevice::WriteOnly);

myPicImg.save(&buffer, "JPG");//用QImage对象储存要写入数据库的照片数据

QVariant var(picdata);

QString sqlstr = "update commodity set Picture=? where Name='" + name + "'";

query.prepare(sqlstr);

query.addBindValue(var);//绑定照片数据作为参数传给？处

if(!query.exec())

{

QMessageBox::information(0, QObject::tr("提示"), "照片写入失败");

}

//刷新网格信息

commodity_model->setTable("commodity_inf");

commodity_model->select();

ui->commodityTableView->setModel(commodity_model);//刷新数据网格（新品入库页）

}

选样照

void MainWindow::on_newUploadPushButton_clicked()

{

QString picturename = QFileDialog::getOpenFileName(this, "选择商品图片", ".", "Image File(*.png *.jpg *.jpeg *.bmp)");

if (picturename.isEmpty()) return;

myPicImg.load(picturename);

ui->newPictureLabel->setPixmap(QPixmap::fromImage(myPicImg));

}

清仓操作

//清仓操作

void MainWindow::on_newClearancePushButton_clicked()

{

QSqlQuery query;

query.exec(QString("delete from commodity where Name='%1'").arg(ui->newNameLineEdit->text()));//删除商品记录

//刷新界面

ui->newNameLineEdit->setText("");

ui->newInputPriceLineEdit->setText("");

ui->newOutputPriceLineEdit->setText("");

ui->newCountSpinBox->setValue(1);

ui->newPictureLabel->clear();

commodity_model->setTable("commodity_inf");

commodity_model->select();

ui->commodityTableView->setModel(commodity_model);//刷新数据网格（新品入库页）

}

商品出售

//商品出售

void MainWindow::on_preSellPushButton_clicked()

{

QSqlQuery query;

if (!myOrdered)

{

query.exec(QString("insert into orders(MemberID, PaySum, PayWay, OTime) values('%1', NULL, NULL, NULL)").arg(myMemberID));

myOrdered = true;

query.exec(QString("select OrderID from orders where OTime IS NULL"));

query.next();

myOrderID = query.value(0).toInt();

}

//下面开始预售

query.exec(QString("select CommodityID from commodity where Name='%1'").arg(ui->preNameComboBox->currentText()));

query.next();

int commodityid = query.value(0).toInt();//本次预售商品编号

int count = ui->preCountSpinBox->value();//预售量

int amount = ui->preCountSpinBox->maximum() - count;//剩余库存量

QSqlDatabase::database().transaction();//开始一个事务

bool insOk = query.exec(QString("insert into orderitems(OrderID, CommodityID, Count) values(%1, %2, %3)").arg(myOrderID).arg(commodityid).arg(count));//新增订单项

bool uptOk = query.exec(QString("update commodity set Amount=%1 where CommodityID=%2").arg(amount).arg(commodityid));//更新库存

if (insOk && uptOk)

{

QSqlDatabase::database().commit();

onPreNameComboBoxChange();

//显示预售清单

QString curtime = QTime::currentTime().toString("hh:mm:ss");

QString curname = ui->preNameComboBox->currentText();

QString curcount = QString::number(count, 10);

QString curoutprice = ui->preOutputPriceLabel->text();

QString curtotal = ui->preTotalLabel->text();

myPaySum += curtotal.toFloat();

QString sell_record = curtime + " " + "售出：" + curname + "rn 数量：" + curcount + "；单价：" + curoutprice + "¥；总价：" + curtotal + "¥";

QListWidgetItem *split = new QListWidgetItem;

split->setText("——.——.——.——.——.——.——.——.——.——.——.——.——.——.——");

split->setTextAlignment(Qt::AlignCenter);

ui->sellListWidget->addItem(split);

ui->sellListWidget->addItem(sell_record);

ui->prePlaceOrderPushButton->setEnabled(true);

QMessageBox::information(0, QObject::tr("提示"), "已加入订单！");

} else {

QSqlDatabase::database().rollback();

}

}

下订单

//下订单

void MainWindow::on_prePlaceOrderPushButton_clicked()

{

QSqlQuery query;

QString otime = QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss");

QSqlDatabase::database().transaction();//开始一个事务

bool ordOk = query.exec(QString("update orders set PaySum=%1, OTime='%2' where OrderID=%3").arg(myPaySum).arg(otime).arg(myOrderID));//下订单

bool uptOk = query.exec(QString("update orderitems set Affirm=1, SendGoods=1 where OrderID=%1").arg(myOrderID));//确认发货

if (ordOk && uptOk)

{

QSqlDatabase::database().commit();

ui->prePlaceOrderPushButton->setEnabled(false);

//显示下单记录

QString order_record = "日 期：" + otime + "rn订 单 号：" + QString(" %1 ").arg(myOrderID) + "rn应付款总额：" + QString(" %1¥").arg(myPaySum) + "rn下 单 成 功！";

QListWidgetItem *split = new QListWidgetItem;

split->setText("***.***.***.***.***.***.***.***.***.***.***.***.***.***.***.***.***.***");

split->setTextAlignment(Qt::AlignCenter);

ui->sellListWidget->addItem(split);

ui->sellListWidget->addItem(order_record);

myPaySum = 0;

QMessageBox::information(0, QObject::tr("提示"), "下单成功！");

commodity_model->setTable("commodity_inf");

commodity_model->select();

ui->commodityTableView->setModel(commodity_model);//刷新数据网格（新品入库页）

} else {

QSqlDatabase::database().rollback();

}

}

mainwidow.h

#ifndef MAINWINDOW_H

#define MAINWINDOW_H

#include <QMainWindow>

#include <QMessageBox>

#include <QFileDialog>

#include <QBuffer>

//#include "opencv2/opencv.hpp"

#include <QSqlDatabase> //MySQL数据库类

#include <QSqlTableModel> //MySQL表模型库

#include <QSqlQuery> //MySQL查询类库

#include <QTime>

#include <QPixmap> //图像处理类库

//using namespace cv;

namespace Ui {

class MainWindow;

}

class MainWindow : public QMainWindow

{

Q_OBJECT

public:

explicit MainWindow(QWidget *parent = 0);

~MainWindow();

void initMainWindow();

void onTableSelectChange(int row); //商品信息数据网格与表单联动

void showCommodityPhoto(); //显示商品样照

void loadPreCommodity(); //加载预售订单页商品名称列表

void onPreNameComboBoxChange(); //预售订单页商品名与表单联动

private slots:

void on_commodityTableView_clicked(const QModelIndex& index);//商品信息数据网格单击事件槽

void on_newPutinStorePushButton_clicked();//入库按钮事件单击事件槽

void on_preCategoryComboBox_currentIndexChanged(int index);//类别与商品名列表联动信息槽

void on_preNameComboBox_currentIndexChanged(int index);//改选商品名信息槽

void on_preCountSpinBox_valueChanged(int arg1);//售出商品数改变信息槽

void on_preSellPushButton_clicked();//"出售"按钮单击事件

void on_prePlaceOrderPushButton_clicked();//下单按钮单击事件

void on_newUploadPushButton_clicked();//上传按钮事件单击事件槽

void on_newClearancePushButton_clicked();//清仓按钮事件单击事件槽

private:

Ui::MainWindow *ui;

QImage myPicImg; //保存商品样照（界面显示）

QSqlTableModel *commodity_model; //访问数据库商品信息视图的模型

QString myMemberID; //会员帐号

bool myOrdered; //是否正在购买(订单已写入数据库)

int myOrderID; //订单编号

float myPaySum; //当前订单累计需要付款的总金额

};

/**访问MySQL数据库的静态方法*/

static bool createMySqlConn()

{

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

sqldb.setHostName("localhost");

sqldb.setDatabaseName("emarket");//数据库名称

sqldb.setUserName("root"); //数据库用户名

sqldb.setPassword("123456"); //登录密码

if (!sqldb.open()) {

QMessageBox::critical(0, QObject::tr("后台数据库连接失败"), "无法创建连接！请检查排除故障后重启程序。", QMessageBox::Cancel);

return false;

}

//QMessageBox::information(0, QObject::tr("后台数据库已启动、正在运行……"), "数据库连接成功！即将启动应用程序。");

//向数据库中插入照片

/*QSqlQuery query(sqldb);

QString photoPath = "D:Qtimgproc21.jpg";//照片不能大于60K

QFile photoFile(photoPath);

if (photoFile.exists())

{

//存入数据库

QByteArray picdata;

photoFile.open(QIODevice::ReadOnly);

picdata = photoFile.readAll();

photoFile.close();

QVariant var(picdata);

QString sqlstr = "update commodity set Picture=? where CommodityID=6";

query.prepare(sqlstr);

query.addBindValue(var);

if(!query.exec())

{

QMessageBox::information(0, QObject::tr("提示"), "照片写入失败");

} else{

QMessageBox::information(0, QObject::tr("提示"), "照片已写入数据库");

}

}

sqldb.close();*/

return true;

}

#endif // MAINWINDOW_H

mainwidow.cpp

#include "mainwindow.h"

#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :

QMainWindow(parent),

ui(new Ui::MainWindow)

{

ui->setupUi(this);

initMainWindow();

}

MainWindow::~MainWindow()

{

delete ui;

}

void MainWindow::initMainWindow()

{

ui->stackedWidget->setCurrentIndex(1);

ui->toolBox->setCurrentIndex(0);

QSqlQueryModel *categoryModel = new QSqlQueryModel(this);//商品类别模型数据

categoryModel->setQuery("select Name from category");

ui->newCategoryComboBox->setModel(categoryModel);//商品类别列表加载（新品入库页）

commodity_model = new QSqlTableModel(this);//商品信息视图

commodity_model->setTable("commodity_inf");

commodity_model->select();

ui->commodityTableView->setModel(commodity_model);//库存商品记录数据网格信息加载（新品入库页）

ui->preCategoryComboBox->setModel(categoryModel);//商品类别列表加载（预售订单页）

loadPreCommodity();//在预售订单页加载商品信息

myMemberID = "b02020622";

//myOrdered = false;

myOrdered = true;

//myOrderID = 0;

myOrderID = 4;

myPaySum = 0;

QListWidgetItem *title = new QListWidgetItem;

title->setText(QString("当 前 订 单 【 编号 %1 】").arg(myOrderID));

title->setTextAlignment(Qt::AlignCenter);

//ui->sellListWidget->addItem(title);

}

void MainWindow::onTableSelectChange(int row)

{

int r = 1;

if(row != 0) r = ui->commodityTableView->currentIndex().row();

QModelIndex index;

index = commodity_model->index(r, 0); //名称

ui->newNameLineEdit->setText(commodity_model->data(index).toString());

index = commodity_model->index(r, 1); //进价

ui->newInputPriceLineEdit->setText(commodity_model->data(index).toString());

index = commodity_model->index(r, 2); //售价

ui->newOutputPriceLineEdit->setText(commodity_model->data(index).toString());

showCommodityPhoto(); //商品样照

QSqlQuery query;

query.exec(QString("select Name from category where CategoryID=(select CategoryID from commodity where Name='%1')").arg(ui->newNameLineEdit->text()));

query.next();

ui->newCategoryComboBox->setCurrentText(query.value(0).toString());//类别联动

}

void MainWindow::showCommodityPhoto()

{

QPixmap photo;

QModelIndex index;

QSqlQueryModel *pictureModel = new QSqlQueryModel(this);//商品样照模型数据

QString name = ui->newNameLineEdit->text();

pictureModel->setQuery("select Picture from commodity where Name='" + name + "'");

index = pictureModel->index(0, 0);

photo.loadFromData(pictureModel->data(index).toByteArray(), "JPG");

ui->newPictureLabel->setPixmap(photo);

}

void MainWindow::loadPreCommodity()

{

QSqlQueryModel *commodityNameModel = new QSqlQueryModel(this);//商品名称模型数据

commodityNameModel->setQuery(QString("select Name from commodity where CategoryID=(select CategoryID from category where Name='%1')").arg(ui->preCategoryComboBox->currentText()));

ui->preNameComboBox->setModel(commodityNameModel);//商品名称列表加载（预售订单页）

onPreNameComboBoxChange();

}

void MainWindow::onPreNameComboBoxChange()

{

QSqlQueryModel *preCommodityModel = new QSqlQueryModel(this);//商品表模型数据

QString name = ui->preNameComboBox->currentText();

preCommodityModel->setQuery("select OutputPrice, Amount, Picture from commodity where Name='" + name + "'");

QModelIndex index;

index = preCommodityModel->index(0, 0); //单价

ui->preOutputPriceLabel->setText(preCommodityModel->data(index).toString());

index = preCommodityModel->index(0, 1); //库存

ui->preAmountLabel->setText(preCommodityModel->data(index).toString());

ui->preCountSpinBox->setMaximum(ui->preAmountLabel->text().toInt());

//下面开始获取和展示照片

QPixmap photo;

index = preCommodityModel->index(0, 2);

photo.loadFromData(preCommodityModel->data(index).toByteArray(), "JPG");

ui->prePictureLabel->setPixmap(photo);

//计算总价

ui->preTotalLabel->setText(QString::number(ui->preOutputPriceLabel->text().toFloat() * ui->preCountSpinBox->value()));

}

void MainWindow::on_commodityTableView_clicked(const QModelIndex &index)

{

onTableSelectChange(1);

}

void MainWindow::on_preCategoryComboBox_currentIndexChanged(int index)

{

loadPreCommodity();

}

void MainWindow::on_preNameComboBox_currentIndexChanged(int index)

{

onPreNameComboBoxChange();

}

void MainWindow::on_preCountSpinBox_valueChanged(int arg1)

{

ui->preTotalLabel->setText(QString::number(ui->preOutputPriceLabel->text().toFloat() * arg1));

}

//商品出售

void MainWindow::on_preSellPushButton_clicked()

{

QSqlQuery query;

if (!myOrdered)

{

query.exec(QString("insert into orders(MemberID, PaySum, PayWay, OTime) values('%1', NULL, NULL, NULL)").arg(myMemberID));

myOrdered = true;

query.exec(QString("select OrderID from orders where OTime IS NULL"));

query.next();

myOrderID = query.value(0).toInt();

}

//下面开始预售

query.exec(QString("select CommodityID from commodity where Name='%1'").arg(ui->preNameComboBox->currentText()));

query.next();

int commodityid = query.value(0).toInt();//本次预售商品编号

int count = ui->preCountSpinBox->value();//预售量

int amount = ui->preCountSpinBox->maximum() - count;//剩余库存量

QSqlDatabase::database().transaction();//开始一个事务

bool insOk = query.exec(QString("insert into orderitems(OrderID, CommodityID, Count) values(%1, %2, %3)").arg(myOrderID).arg(commodityid).arg(count));//新增订单项

bool uptOk = query.exec(QString("update commodity set Amount=%1 where CommodityID=%2").arg(amount).arg(commodityid));//更新库存

if (insOk && uptOk)

{

QSqlDatabase::database().commit();

onPreNameComboBoxChange();

//显示预售清单

QString curtime = QTime::currentTime().toString("hh:mm:ss");

QString curname = ui->preNameComboBox->currentText();

QString curcount = QString::number(count, 10);

QString curoutprice = ui->preOutputPriceLabel->text();

QString curtotal = ui->preTotalLabel->text();

myPaySum += curtotal.toFloat();

QString sell_record = curtime + " " + "售出：" + curname + "rn 数量：" + curcount + "；单价：" + curoutprice + "¥；总价：" + curtotal + "¥";

QListWidgetItem *split = new QListWidgetItem;

split->setText("——.——.——.——.——.——.——.——.——.——.——.——.——.——.——");

split->setTextAlignment(Qt::AlignCenter);

ui->sellListWidget->addItem(split);

ui->sellListWidget->addItem(sell_record);

ui->prePlaceOrderPushButton->setEnabled(true);

QMessageBox::information(0, QObject::tr("提示"), "已加入订单！");

} else {

QSqlDatabase::database().rollback();

}

}

//下订单

void MainWindow::on_prePlaceOrderPushButton_clicked()

{

QSqlQuery query;

QString otime = QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss");

QSqlDatabase::database().transaction();//开始一个事务

bool ordOk = query.exec(QString("update orders set PaySum=%1, OTime='%2' where OrderID=%3").arg(myPaySum).arg(otime).arg(myOrderID));//下订单

bool uptOk = query.exec(QString("update orderitems set Affirm=1, SendGoods=1 where OrderID=%1").arg(myOrderID));//确认发货

if (ordOk && uptOk)

{

QSqlDatabase::database().commit();

ui->prePlaceOrderPushButton->setEnabled(false);

//显示下单记录

QString order_record = "日 期：" + otime + "rn订 单 号：" + QString(" %1 ").arg(myOrderID) + "rn应付款总额：" + QString(" %1¥").arg(myPaySum) + "rn下 单 成 功！";

QListWidgetItem *split = new QListWidgetItem;

split->setText("***.***.***.***.***.***.***.***.***.***.***.***.***.***.***.***.***.***");

split->setTextAlignment(Qt::AlignCenter);

ui->sellListWidget->addItem(split);

ui->sellListWidget->addItem(order_record);

myPaySum = 0;

QMessageBox::information(0, QObject::tr("提示"), "下单成功！");

commodity_model->setTable("commodity_inf");

commodity_model->select();

ui->commodityTableView->setModel(commodity_model);//刷新数据网格（新品入库页）

} else {

QSqlDatabase::database().rollback();

}

}

//选样照

void MainWindow::on_newUploadPushButton_clicked()

{

QString picturename = QFileDialog::getOpenFileName(this, "选择商品图片", ".", "Image File(*.png *.jpg *.jpeg *.bmp)");

if (picturename.isEmpty()) return;

myPicImg.load(picturename);

ui->newPictureLabel->setPixmap(QPixmap::fromImage(myPicImg));

}

//入库操作

void MainWindow::on_newPutinStorePushButton_clicked()

{

QSqlQuery query;

query.exec(QString("select CategoryID from category where Name='%1'").

arg(ui->newCategoryComboBox->currentText()));//根据类别名查询类别ID

query.next();

int categoryid = query.value(0).toInt();//将要入库的商品类别

QString name = ui->newNameLineEdit->text();//商品名称

float inputprice = ui->newInputPriceLineEdit->text().toFloat();//进价

float outputprice = ui->newOutputPriceLineEdit->text().toFloat();//售价

int count = ui->newCountSpinBox->value();//入库量

query.exec(QString("insert into commodity(CategoryID, Name, Picture, InputPrice, OutputPrice, Amount) values(%1, '%2', NULL, %3, %4, %5)").

arg(categoryid).arg(name).arg(inputprice).arg(outputprice).arg(count));//插入新入库的商品记录

//插入照片

QByteArray picdata;

QBuffer buffer(&picdata);

buffer.open(QIODevice::WriteOnly);

myPicImg.save(&buffer, "JPG");//用QImage对象储存要写入数据库的照片数据

QVariant var(picdata);

QString sqlstr = "update commodity set Picture=? where Name='" + name + "'";

query.prepare(sqlstr);

query.addBindValue(var);//绑定照片数据作为参数传给？处

if(!query.exec())

{

QMessageBox::information(0, QObject::tr("提示"), "照片写入失败");

}

//刷新网格信息

commodity_model->setTable("commodity_inf");

commodity_model->select();

ui->commodityTableView->setModel(commodity_model);//刷新数据网格（新品入库页）

}

//清仓操作

void MainWindow::on_newClearancePushButton_clicked()

{

QSqlQuery query;

query.exec(QString("delete from commodity where Name='%1'").arg(ui->newNameLineEdit->text()));//删除商品记录

//刷新界面

ui->newNameLineEdit->setText("");

ui->newInputPriceLineEdit->setText("");

ui->newOutputPriceLineEdit->setText("");

ui->newCountSpinBox->setValue(1);

ui->newPictureLabel->clear();

commodity_model->setTable("commodity_inf");

commodity_model->select();

ui->commodityTableView->setModel(commodity_model);//刷新数据网格（新品入库页）

}

main.cpp

#include "mainwindow.h"

#include <QApplication>

#include "logindialog.h"

#include <QProcess>

int main(int argc, char *argv[])

{

QApplication a(argc, argv);

if(!createMySqlConn())

{

QProcess process;

process.start("C:/Program Files/MySQL/MySQL Server 5.6/bin/mysqld.exe");

if(!createMySqlConn()) return 1;

}

LoginDialog logindlg;

if(logindlg.exec() == QDialog::Accepted)

{

MainWindow w;

w.show();

return a.exec();

}

else

{

return 0;

}

}

eMarket.pro

#-------------------------------------------------

#

# Project created by QtCreator 2021-09-13T20:26:29

#

#-------------------------------------------------

QT += core gui

QT += sql

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = eMarket

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 6.0.0

SOURCES +=

main.cpp

mainwindow.cpp

logindialog.cpp

HEADERS +=

mainwindow.h

logindialog.h

FORMS +=

mainwindow.ui

logindialog.ui

四、知识点总结

1、界面设计

控件、布局的使用

2、数据库操作

 QSqlQueryModel 是 QSqlTableModel 的父类。QSqlQueryModel 封装了执行 SELECT 语句从数据库查询数据的功能，但是 QSqlQueryModel 只能作为只读数据源使用，不可以编辑数据 。

QSqlQueryModel *categoryModel = new QSqlQueryModel(this);//创建了一个商品类别表模型，与商品类别表通信

categoryModel->setQuery();//执行SQL语句操作

ui->newCategoryComboBox->setModel(categoryModel);//将查询的结果当作商品类别列表加载（新品入库页）

QSqlQueryModel *categoryModel = new QSqlQueryModel(this);//商品类别模型数据

categoryModel->setQuery("select Name from category");

ui->newCategoryComboBox->setModel(categoryModel);//商品类别列表加载（新品入库页）

QPixmap photo;

QModelIndex index;

QSqlQueryModel *pictureModel = new QSqlQueryModel(this);//商品样照模型数据

QString name = ui->newNameLineEdit->text();

pictureModel->setQuery("select Picture from commodity where Name='" + name + "'");

index = pictureModel->index(0, 0);

photo.loadFromData(pictureModel->data(index).toByteArray(), "JPG");

ui->newPictureLabel->setPixmap(photo);

//插入照片

QByteArray picdata;

QBuffer buffer(&picdata);

buffer.open(QIODevice::WriteOnly);

myPicImg.save(&buffer, "JPG");//用QImage对象储存要写入数据库的照片数据

QVariant var(picdata);

QString sqlstr = "update commodity set Picture=? where Name='" + name + "'";

query.prepare(sqlstr);

query.addBindValue(var);//绑定照片数据作为参数传给？处

if(!query.exec())

{

QMessageBox::information(0, QObject::tr("提示"), "照片写入失败");

}

1 QSqlQuery::next() 从数据库的开头一直往下找，如果某一行存了数据则返回1，如果是1个空行，则返回0 2 QSqlQuery::value(0) 如果存入数据库的数据是00 11 11 11 11 则打印出来的是QVariant(QString, "00111111") 转成字符串类型 QSqlQuery::value(0).toString()则打印出来的结果为 00 11 11 11 11 3 QSqlQuery::value(1).toString() 打印出来的则是"" 4 QSqlQuery::size() 数据库中如果存了多少条数据，这个值就是多少。

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