01-15

#include "ui_widget.h"

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

    //判断是否有该数据库
    if(!db.contains("stuInfo.db"))
    {
        //说明数据库不存在 则创建
        db=QSqlDatabase::addDatabase("QSQLITE");//增加一个数据库，驱动为sqlite3
        //给创建的数据库设置数据库名
        db.setDatabaseName("stuInfo");
    }
    //打开数据库
    if(!db.open())
    {
        QMessageBox::information(this,"","打开数据库失败");
        return;
    }
    //创建数据库表
    //实例化一个执行sql语句的对象
    QSqlQuery query;
    //准备sql语句
    QString sql="create table if not exists stu_info_table("
                "id integer primary key autoincrement,"
                "numb integer,"
                "name varchar(20),"
                "sex varchar(4),"
                "score integer)";
    //执行sql语句
    if(query.exec(sql))
    {
        QMessageBox::information(this,"","创建数据库表成功");
    }
    else
    {
        QMessageBox::information(this,"","创建数据库表失败");
        return;
    }
    on_showBtn_clicked();
}

Widget::~Widget()
{
    delete ui;
}

//添加按钮对应的槽函数处理
void Widget::on_addBtn_clicked()
{
    //获取ui界面上学生信息
    int numb=ui->numEdit->text().toUInt();
    QString name=ui->nameEdit->text();
    QString sex=ui->sexEdit->text();
    int score=ui->scoreEdit->text().toUInt();

    //判断用户是否填写完整信息
    if(numb==0||name.isEmpty()||sex.isEmpty()||score==0)
    {
        QMessageBox::information(this,"","请将信息填写完整");
        return;
    }
    //实例化一个执行sql语句的对象
    QSqlQuery query;
    //准备sql语句
    QString sql=QString("insert into stu_info_table (numb,name,sex,score)"
                "values(%1,'%2','%3',%4)").arg(numb).arg(name).arg(sex).arg(score);

    //执行sql语句
    if(query.exec(sql))
    {
        QMessageBox::information(this,"","添加成功");
    }
    else
    {
        QMessageBox::information(this,"","添加失败");
    }
    ui->numEdit->clear();
    ui->nameEdit->clear();
    ui->sexEdit->clear();
    ui->scoreEdit->clear();
    ui->tableWidget->clearContents();
    on_showBtn_clicked();
}

//显示按钮对应槽函数处理
void Widget::on_showBtn_clicked()
{
    //准备sql语句
    QSqlQuery query;
    QString sql="select * from stu_info_table";
    if(!query.exec(sql))
    {
        QMessageBox::information(this,"","查询失败");
        return;
    }


    //所查询的信息就已经存放到query对象中
    int i=0;//记录行号
    while(query.next())
    {
        for(int j=0;j<query.record().count();j++)
        {
            ui->tableWidget->setItem(i,j,new QTableWidgetItem(query.value(j+1).toString()));
        }
        i++;//行数递增
    }
}

void Widget::on_deleteBtn_clicked()
{
    int numb=ui->numEdit->text().toUInt();
    QSqlQuery query;
    QString sql=QString("delete from stu_info_table where numb=%1").arg(numb);
    if(query.exec(sql))
    {
        QMessageBox::information(this,"","执行成功");
    }
    else
    {
        QMessageBox::information(this,"","执行失败");
    }
    ui->tableWidget->clearContents();
    on_showBtn_clicked();
}

void Widget::on_revbtn_clicked()
{
    QSqlQuery query;
    int numb=ui->numEdit->text().toUInt();
    QString name=ui->nameEdit->text();
    QString sex=ui->sexEdit->text();
    int score=ui->scoreEdit->text().toUInt();
    if(!name.isEmpty())
    {
        QString sql=QString("update stu_info_table set name='%1' where numb=%2").arg(name).arg(numb);
        query.exec(sql);
    }
    if(!sex.isEmpty())
    {
        QString sql=QString("update stu_info_table set sex='%1' where numb=%2").arg(sex).arg(numb);
        query.exec(sql);
    }
    if(!score)
    {
        QString sql=QString("update stu_info_table set score=%1 where numb=%2").arg(score).arg(numb);
        query.exec(sql);
    }
    ui->tableWidget->clearContents();
    on_showBtn_clicked();
}