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1.连接数据库
先来看下连接数据库的效果图。
“连接数据库”按钮的槽函数如下：
void MainWindow::on_pushButton_connectDataBase_clicked(){ //连接数据库 db.setHostName("127.0.0.1"); db.setPort(3306); db.setDatabaseName("test");//数据库名称 db.setUserName("root");//用户名 db.setPassword("root");//密码 qDebug()<<"available drivers:"; QStringList drivers = QSqlDatabase::drivers(); for(auto driver: drivers) qDebug() << driver; bool ok = db.open(); if(ok) { QMessageBox::information(this, "提示","数据库连接成功"); qDebug()<<"数据库连接成功"; } else { QMessageBox::information(this, "提示","数据库连接失败"); this->close(); qDebug()<<"数据库连接失败"; } //若数据库中没有表，则新建 QSqlQuery query; QString createTableUser="create table if not exists user(name varchar(8),age int(255), " "sex varchar(8), number int(255));"; query.exec(createTableUser);}若在数据库名等信息没有填错的情况下，数据库连接失败，并打印以下信息，情参考该链接解决：https://www.yisu.com/article/281192.htm
当运行点击"连接数据库"按钮后，会根据信息连接对应的数据库，若连接的该数据库没有user表时，会自动创建一个user表，创建的表信息如下图所示，该图为Navicat Premium 15软件内的截图。
2.查询数据库并显示在QTableView上
先看下效果图：
首先定义一个QSqlQueryModel数据模型，并于对应的QTableView绑定，如下：
QSqlQueryModel *userMode;//数据模型userMode = new QSqlQueryModel(ui->tableView);//绑定设置点击查询的槽函数：
//查询void MainWindow::on_pushButton_query_clicked(){ userMode->setQuery("select * from user;"); ReshowTable();}void MainWindow::ReshowTable(){ userMode->setHeaderData(0,Qt::Horizontal,tr("姓名")); userMode->setHeaderData(1,Qt::Horizontal,tr("年龄")); userMode->setHeaderData(2,Qt::Horizontal,tr("性别")); userMode->setHeaderData(3,Qt::Horizontal,tr("手机号")); ui->tableView->setModel(userMode);}3.添加
先看添加的效果图：
在信息输入内对应填写各信息，填写完成后点击“添加”按钮，可添加完成输入的对应信息，与数据库内容同步，添加按钮的槽函数：
//添加void MainWindow::on_pushButton_add_clicked(){ QString name = ui->lineEdit_name->text(); QString age = ui->lineEdit_age->text(); QString sex = ui->lineEdit_sex->text(); QString number = ui->lineEdit_number->text(); QSqlQuery query; QString str1 = "'" + name +"','" + age + "','" +sex+"','"+number+"'"; QString str = "insert into user(name, age, sex, number) values(" + str1 + ");"; query.exec(str); userMode->setQuery("select * from user;"); ReshowTable();}4.修改
修改的效果图：
设置点击表格中的某一列，然后将点击那一列的信息显示在编辑信息的文本框内，修改完成后点击修改即可完成修改，对应函数如下函数：
void MainWindow::on_tableView_pressed(const QModelIndex &index){ QString name = userMode->data(userMode->index(index.row(), 0)).toString(); QString age = userMode->data(userMode->index(index.row(), 1)).toString(); QString sex = userMode->data(userMode->index(index.row(), 2)).toString(); QString number = userMode->data(userMode->index(index.row(), 3)).toString(); ui->lineEdit_name->setText(name); ui->lineEdit_age->setText(age); ui->lineEdit_sex->setText(sex); ui->lineEdit_number->setText(number);}//修改void MainWindow::on_pushButton_change_clicked(){ QSqlQuery query; QString str = "update user set name='" + ui->lineEdit_name->text() + "',age='" + ui->lineEdit_age->text() + "',sex='" + ui->lineEdit_sex->text() + "' where number='" + ui->lineEdit_number->text() + "';"; query.exec(str); QMessageBox::information(this, "修改成功", "表信息修改成功"); userMode->setQuery("select * from user;"); ReshowTable();}5.删除
删除的效果图：
删除的槽函数如下：
//删除void MainWindow::on_pushButton_delete_clicked(){ QSqlQuery query; int currentrow = ui->tableView->currentIndex().row(); userMode->removeRow(currentrow); if(currentrow != -1)//若选中一行 { int ok = QMessageBox::warning(this,tr("删除当前行!"),tr("你确定删除当前行吗？"), QMessageBox::Yes,QMessageBox::No); //如确认删除 if(ok == QMessageBox::Yes) { userMode->removeRow(currentrow); QString name = userMode->data(userMode->index(currentrow,0)).toString();//获取姓名 QString del = "delete from user where name='" + name + "';"; query.exec(del); userMode->setQuery("select * from user"); ui->tableView->setModel(userMode); QMessageBox::information(this, "删除成功", "所选信息删除成功"); } } else QMessageBox::information(this, "提示", "请选择你要删除的信息行");}6.总代码
mainwidow.h
#ifndef MAINWINDOW_H#define MAINWINDOW_H#include <QMainWindow>#include <QMessageBox>#include <QSqlDatabase>#include <QSqlQuery>#include <QDebug>#include <QSqlQueryModel>QT_BEGIN_NAMESPACEnamespace Ui { class MainWindow; }QT_END_NAMESPACEclass MainWindow : public QMainWindow{ Q_OBJECTpublic: MainWindow(QWidget *parent = nullptr); ~MainWindow();private slots: void ReshowTable(); void on_pushButton_connectDataBase_clicked(); void on_pushButton_add_clicked(); void on_pushButton_delete_clicked(); void on_pushButton_change_clicked(); void on_pushButton_query_clicked(); void on_tableView_pressed(const QModelIndex &index);private: Ui::MainWindow *ui; QSqlDatabase db= QSqlDatabase::addDatabase("QMYSQL"); QSqlQueryModel *userMode;//数据模型};#endif // MAINWINDOW_Hmainwindow.cpp
#include "mainwindow.h"#include "ui_mainwindow.h"MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) , ui(new Ui::MainWindow){ ui->setupUi(this); userMode = new QSqlQueryModel(ui->tableView);//绑定}MainWindow::~MainWindow(){ delete ui;}void MainWindow::ReshowTable(){ userMode->setHeaderData(0,Qt::Horizontal,tr("姓名")); userMode->setHeaderData(1,Qt::Horizontal,tr("年龄")); userMode->setHeaderData(2,Qt::Horizontal,tr("性别")); userMode->setHeaderData(3,Qt::Horizontal,tr("手机号")); ui->tableView->setModel(userMode);}void MainWindow::on_pushButton_connectDataBase_clicked(){ //连接数据库 db.setHostName("127.0.0.1"); db.setPort(3306); db.setDatabaseName("test");//数据库名称 db.setUserName("root");//用户名 db.setPassword("root");//密码 qDebug()<<"available drivers:"; QStringList drivers = QSqlDatabase::drivers(); for(auto driver: drivers) qDebug() << driver; bool ok = db.open(); if(ok) { QMessageBox::information(this, "提示","数据库连接成功"); qDebug()<<"数据库连接成功"; } else { QMessageBox::information(this, "提示","数据库连接失败"); this->close(); qDebug()<<"数据库连接失败"; } //若数据库中没有表，则新建 QSqlQuery query; QString createTableUser="create table if not exists user(name varchar(8),age int(255), " "sex varchar(8), number int(255));"; query.exec(createTableUser);}//添加void MainWindow::on_pushButton_add_clicked(){ QString name = ui->lineEdit_name->text(); QString age = ui->lineEdit_age->text(); QString sex = ui->lineEdit_sex->text(); QString number = ui->lineEdit_number->text(); QSqlQuery query; QString str1 = "'" + name +"','" + age + "','" +sex+"','"+number+"'"; QString str = "insert into user(name, age, sex, number) values(" + str1 + ");"; query.exec(str); userMode->setQuery("select * from user;"); ReshowTable();}//删除void MainWindow::on_pushButton_delete_clicked(){ QSqlQuery query; int currentrow = ui->tableView->currentIndex().row(); userMode->removeRow(currentrow); if(currentrow != -1)//若选中一行 { int ok = QMessageBox::warning(this,tr("删除当前行!"),tr("你确定删除当前行吗？"), QMessageBox::Yes,QMessageBox::No); //如确认删除 if(ok == QMessageBox::Yes) { userMode->removeRow(currentrow); QString name = userMode->data(userMode->index(currentrow,0)).toString();//获取姓名 QString del = "delete from user where name='" + name + "';"; query.exec(del); userMode->setQuery("select * from user"); ui->tableView->setModel(userMode); QMessageBox::information(this, "删除成功", "所选信息删除成功"); } } else QMessageBox::information(this, "提示", "请选择你要删除的信息行");}//修改void MainWindow::on_pushButton_change_clicked(){ QSqlQuery query; QString str = "update user set name='" + ui->lineEdit_name->text() + "',age='" + ui->lineEdit_age->text() + "',sex='" + ui->lineEdit_sex->text() + "' where number='" + ui->lineEdit_number->text() + "';"; query.exec(str); QMessageBox::information(this, "修改成功", "表信息修改成功"); userMode->setQuery("select * from user;"); ReshowTable();}//查询void MainWindow::on_pushButton_query_clicked(){ userMode->setQuery("select * from user;"); ReshowTable();}void MainWindow::on_tableView_pressed(const QModelIndex &index){ QString name = userMode->data(userMode->index(index.row(), 0)).toString(); QString age = userMode->data(userMode->index(index.row(), 1)).toString(); QString sex = userMode->data(userMode->index(index.row(), 2)).toString(); QString number = userMode->data(userMode->index(index.row(), 3)).toString(); ui->lineEdit_name->setText(name); ui->lineEdit_age->setText(age); ui->lineEdit_sex->setText(sex); ui->lineEdit_number->setText(number);}感谢各位的阅读，以上就是“Qt怎么连接数据库并实现数据库增删改查”的内容了，经过本文的学习后，相信大家对Qt怎么连接数据库并实现数据库增删改查这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是编程网，小编将为大家推送更多相关知识点的文章，欢迎关注！
