qt连接MySQL的提示

Question

#include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    db=QSqlDatabase::addDatabase("QMYSQL");
    db.setDatabaseName(" mydatabase");
    db.setHostName("localhost");
    db.setUserName("root");
    db.setPassword("123456");
    db.setPort(3306);
    if(db.open()){
       QMessageBox::information(this,"连接提示","连接成功");
    }
    else{
         QMessageBox::warning(this,"连接提示","连接失败");
    }
}

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

为什么qt运行后既没有连接成功也没有连接失败

Answer 1

运行的还是原来的文件