qt creator mysql

qt 连接
https://doc.qt.io/qt-5/designer-using-a-ui-file.html#automatic-connections

https://www.bilibili.com/video/BV1Jk4y167tt?p=1

教程:
https://www.bilibili.com/video/BV1XW411x7NU?p=85

11 参考

Qt5.13编译mysql5.6.45-x64驱动（Win10）
https://blog.youkuaiyun.com/xiaohuihuihuige/article/details/105167430

需要自己编译

C:\Qt\Qt5.13.0\5.13.0\Src\qtbase\src\plugins\sqldrivers\mysql

Cannot read C:/Qt/Qt5.13.0/5.13.0/Src/qtbase/src/plugins/sqldrivers/qtsqldrivers-config.pri: No such file or directory
Project ERROR: Library 'mysql' is not defined.
Cannot read C:/qtsqldrivers-config.pri: No such file or directory
Cannot read /mkspecs/modules-inst/qt_plugin_qsqlmysql.pri: No such file or directory
C:/Qt/Qt5.13.0/5.13.0/mingw73_64/mkspecs/features/qt_plugin.prf(81): Variable QT_PLUGINS is not defined.
Project ERROR: Library 'mysql' is not defined.

C:\Program Files\MySQL\MySQL Server 8.0\

TARGET = qsqlmysql

HEADERS += $$PWD/qsql_mysql_p.h
SOURCES += $$PWD/qsql_mysql.cpp $$PWD/main.cpp

#QMAKE_USE += mysql

OTHER_FILES += mysql.json

PLUGIN_CLASS_NAME = QMYSQLDriverPlugin


win32:LIBS += $$quote( C:\Program Files\MySQL\MySQL Server 8.0\lib\libmysql.lib )
INCLUDEPATH += $$quote( C:\Program Files\MySQL\MySQL Server 8.0/include )
DEPENDPATH += $$quote( C:\Program Files\MySQL\MySQL Server 8.0/include )



include(../qsqldriverbase.pri)

6、dll文件的拷贝覆盖
dll文件生成成功后，将 qsqlmysql.dll 和 qsqlmysqld.dll 两个文件拷贝到两个指定目录内
本人的是：
C:\Qt\Qt5.13.0\5.13.0\mingw73_64\bin
C:\Qt\Qt5.13.0\5.13.0\mingw73_64\plugins\sqldrivers

进一步解决问题

参考:
解决 QMYSQL driver not loaded 问题 QT5.12.2 连接数据库MySQL Server8.0
https://blog.youkuaiyun.com/monkey988/article/details/89159777

C:\Qt\Qt5.13.0\5.13.0\mingw73_64\bin
C:\Program Files\MySQL\MySQL Server 8.0\bin
C:\Program Files\MySQL\MySQL Server 8.0\lib

MinGW 64bit编译器和MSVC2017 64bit编译器成功连接到MySQL.
具体步骤:
目标路径:C:\Qt\Qt5.13.0\5.13.0\mingw73_64\bin
1.打开路径: C:\Program Files\MySQL\MySQL Server 8.0\lib
找到libmysql.dll ,libmysql.lib复制到目标路径
2.打开路径: C:\Program Files\MySQL\MySQL Server 8.0\bin
找到ssleay32.dll ,libeay32.dll复制到目标路径。
成功解决。

运行的代码:

#include "widget.h"
#include "ui_widget.h"
#include <QSqlDatabase>
#include <QDebug>
#include <QMessageBox>
#include <QSqlError>
#include <QSqlQuery>

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

    //打印qt支持的数据库驱动
    //为啥没有MySql数据库呢
    //("QSQLITE", "QODBC", "QODBC3", "QPSQL", "QPSQL7")
    qDebug() << QSqlDatabase::drivers();
    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
    db.setHostName("127.0.0.1");
    db.setUserName("root");
    db.setPassword("123456");
    db.setDatabaseName("info");

    //连接数据库
    if(! db.open()){
        QMessageBox::warning(this, "错误", db.lastError().text());
        return ;
    }
    else
    {
       qDebug()<<"连接成功！！！";

    }

    QSqlQuery query ;
    bool status = query.exec("create table brand (id int primary key auto_increment, factory varchar(255), name varchar(255), price int, sum int, sell int, last int);");
    qDebug() <<"status = " << status;
}

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