Qt实现简单的增删改查-QT开发中文网

1、首先在.pro文件中加入 QT += sql widgets

2、创建连接类connection.h

static bool createConnection()
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName("my.db");
    if(!db.open())
    {
        QMessageBox::critical(0,"Cannot open database1","Unable to establish a database",QMessageBox::Cancel);
        return false;
    }
    QSqlQuery query;

    //创建student表
    query.exec("create table student(id int primary key,name varchar,course int");
    query.exec("insert into student values(,'李强',11)");
    query.exec("insert into student values(2,'马良',11)");
    query.exec("insert into student values(3,'孙红',12)");

    //创建course表
    query.exec("create table course (id int primary key,name varchar,teacher varchar)");
    query.exec("insert into course values(10,'数学','王老师')");
    query.exec("create into course values (11,'英语','张老师')");
    query.exec("insert into course values(12,'计算机','白老师')");

    return  true;
}

3、mainwindow.h

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    void on_pushButton_clicked();//修改提交

    void on_pushButton2_clicked();//撤销修改
    void on_pushButton3_clicked();//添加记录

    void on_pushButton4_clicked();//删除选中行
    void on_pushButton5_clicked();//按id升序排列

    void on_pushButton6_clicked();//按id 降序排列
    void on_pushButton7_clicked();//查询

    void on_pushButton8_clicked();//显示列表


private:
    Ui::MainWindow *ui;
    QSqlTableModel * model;
};

4、mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include<QSqlQueryModel>
#include<QSqlTableModel>
#include<QSqlRelationalTableModel>
#include<QTableView>
#include<QMessageBox>
#include<QSqlError>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    model = new QSqlTableModel(this);
    model ->setTable("student");
    model->select();

    //设置编辑策略
    model->setEditStrategy(QSqlTableModel::OnManualSubmit);
    ui->tableView->setModel(model);
}

MainWindow::~MainWindow()
{
    delete ui;
}
//修改提交
void MainWindow::on_pushButton_clicked()
{
    //开始事务操作
    model->database().transaction();
    if(model->submitAll())
    {
        QMessageBox::information(this,tr("tableModel"),tr("数据修改成功"));
    }
    else
    {
        model->database().rollback();  //回滚
        QMessageBox::warning(this,tr("tableModel"),tr("数据库错误：%1").arg(model->lastError().text()),
                             QMessageBox::Ok);
    }
}
//撤销修改
void MainWindow::on_pushButton2_clicked()
{
    model->revertAll();//事件回滚
}
//添加记录
void MainWindow::on_pushButton3_clicked()
{
    //获取表的行数
    int rowNum = model->rowCount();
    int id = 10;

    //添加一行
    model->insertRow(rowNum);
    model->setData(model->index(rowNum,0),id);

    //可以直接提交
    model->submitAll();
}
//删除选中行
void MainWindow::on_pushButton4_clicked()
{
    //获取选中的行
    int curRow = ui->tableView->currentIndex().row();

    //删除该行
    model->removeRow(curRow);
    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);
    if(ok == QMessageBox::No)
    {
        //如果不删除则撤销
        model->revertAll();
    }
    else  //否则，在数据库中删除该行
    {
        model->submitAll();
    }
}
//按id升序排列
void MainWindow::on_pushButton5_clicked()
{
    //id字段  即第0列，升序排列
    model->setSort(0,Qt::AscendingOrder);
    model->select();
}
//按id 降序排列
void MainWindow::on_pushButton6_clicked()
{
    model->setSort(0,Qt::DescendingOrder);
    model->select();
}
//查询
void MainWindow::on_pushButton7_clicked()
{
    QString name = ui->lineEdit->text();

    //根据姓名进行筛选，一定要使用单引号
    model->setFilter(QString("name = '%1").arg(name));
    model->select();
}
//显示列表
void MainWindow::on_pushButton8_clicked()
{
    model->setTable("student");
    model->select();
}

5、在main.cpp中添加 if(!createConnection()) return 1;

6、mainwindow.ui