QSqlDatabase: MYSQL driver not loaded

Cervo2paille

Hey everyone,

I followed the documentation to put in place a database.

But i got the following warning when i click :

QSqlDatabase: MYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QODBC QPSQL

See my code :

#include "pageinscription.h"
#include "ui_pageinscription.h"

#include <QSqlQuery>

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

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

void pageinscription::inscrire()
{
    database = QSqlDatabase::addDatabase("MYSQL");
    database.setHostName("localhost");
    database.setDatabaseName("bossom");
    database.setUserName("root");
    database.setPassword("");


    if (database.open()) {
      QString identifiant = ui->identifiant->text();
      QString motdepasse = ui->motdepasse->text();

      QSqlQuery qry;
      qry.prepare("INSERT INTO utilisateur (identifiant, motdepasse)"
                  "VALUES (:utilisateur,:motdepasse)");
      qry.bindValue(":identifiant", identifiant);
      qry.bindValue(":motdepasse", motdepasse);

      if(qry.exec()) {
          QMessageBox::information(this,"Inséré","Vous êtes bien inscrits");
      } else{
        QMessageBox::information(this,"Pas inséré","Les données ne se sont pas bien insérées");
      }
    } else {
        QMessageBox::information(this,"Not connected","Database is not connected");
    }
}


void pageinscription::on_pushButton_2_clicked()
{
    database = QSqlDatabase::addDatabase("MYSQL");
    database.setHostName("localhost");
    database.setDatabaseName("bossom");
    database.setUserName("bossom");
    database.setPassword("bossom");
    bool ok = database.open();

    if (database.open()) {
      QString identifiant = ui->identifiant->text();
      QString motdepasse = ui->motdepasse->text();

      QSqlQuery qry;
      qry.prepare("INSERT INTO utilisateur (identifiant, motdepasse)"
                  "VALUES (:utilisateur,:motdepasse)");
      qry.bindValue(":identifiant", identifiant);
      qry.bindValue(":motdepasse", motdepasse);

      if(qry.exec()) {
          QMessageBox::information(this,"Inséré","Vous êtes bien inscrits");
      } else{
        QMessageBox::information(this,"Pas inséré","Les données ne se sont pas bien insérées");
      }
    } else {
        QMessageBox::information(this,"Not connected","Database is not connected");
    }
}

Thank you :)

JonB

@Cervo2paille
Since you want to access a MySQL database what did you do about installing the MySQL driver?

SGaist

Hi,

Beside the question of @JonB, you also have a typo. It's the QMYSQL driver that you are trying to load.

Cervo2paille

@SGaist Thanks for your answer.
In fact there was an error in my "QMYSQL".

I followed the doc : https://doc.qt.io/qt-6/sql-driver.html#qmysql
But i got the same error : it didn't work, i got the same message.
Someone has a good tutorial to connect to my MySQL (Xampp) ?
I copied the lib and dll in my compilator, in my project... so way.

Thanks

jsulm

@Cervo2paille said in QSqlDatabase: MYSQL driver not loaded:

I followed the doc : https://doc.qt.io/qt-6/sql-driver.html#qmysql

So, did you build and install the driver for MySQL? See the "How to Build the QMYSQL Plugin on Windows" chapter in the link you posted.

Cervo2paille

@jsulm Hey,
Sure i did. And after that I saw the note that notice it don't work and we must install "full MySQL Server (x64 only) or the MariaDB C Connector". I tried... and got the same error, again. :)
Thanks

jsulm

@Cervo2paille said in QSqlDatabase: MYSQL driver not loaded:

I tried... and got the same error, again. :)

What exactly did you try?
You need to install MariaDB C Connector before you build the plug-in. And then you pass the paths to the CMake call like shown in the documentation:

qt-cmake -G Ninja <qt_installation_path>\Src\qtbase\src\plugins\sqldrivers -DCMAKE_INSTALL_PREFIX=<qt_installation_path>\<platform> -DMySQL_INCLUDE_DIR="C:\mysql-8.0.22-winx64\include" -DMySQL_LIBRARY="C:\mysql-8.0.22-winx64\lib\libmysql.lib"

So, did you do this?

And one more question: when do you get this plug-in not loaded error: when you start your app from QtCreator or after deployment?

Cervo2paille

@jsulm You're right i got a problem on this line.
I addapted to my system :

qt-cmake -G Ninja D:\Qt\6.3.1\mingw_64\bin -DCMAKE_INSTALL_PREFIX="D:\Qt\6.3.1\mingw_64" -DMySQL_INCLUDE_DIR="D:\Program Files\MySQL\MySQL Server 8.0\include" -DMySQL_LIBRARY="D:\Program Files\MySQL\MySQL Server 8.0\lib\libmysql.lib"

But i got a

'qt-cmake' is not recognized as an internal command

or external, an executable program or a batch file.

I installed it , during the installation accepted to add to my Windows path the cmake... but it didn't worked.

Thank you for your time

jsulm

@Cervo2paille said in QSqlDatabase: MYSQL driver not loaded:

I installed it , during the installation accepted to add to my Windows path the cmake

qt_cmake should be part of your Qt installation, simply use full path to it.

Cervo2paille

Thanks
But here we go again

The 3 files are inside the project, where the documentation wants me to do :

MSVC runtime is installed.

Maybe the problem come from the commands... i can see if they where well executed.

Near to success... bot not yet.
Thanks.

Savitha

@Cervo2paille I think you must include the exe folder path in environmental "Path" variable

jsulm

@Cervo2paille It looks like it is actually working? You just messed up with connections.

Cervo2paille

This post is deleted!

Cervo2paille

@jsulm Added Cmake Path and retry the commands. In fact, the commands seems to not be passed because here, they gave me an error :

C:\Users\flebourgeois\build-sqldrivers>qt-cmake -G Ninja D:\Users\flebourgeois\Documents\QT_Projets\blossom -DCMAKE_INSTALL_PREFIX="D:\Qt\6.3.1\mingw_64" -DMySQL_INCLUDE_DIR="D:\Program Files\MySQL\MySQL Server 8.0\include" -DMySQL_LIBRARY="D:\Program Files\MySQL\MySQL Server 8.0\lib\libmysql.lib"
CMake Error: CMake was unable to find a build program corresponding to "Ninja".  CMAKE_MAKE_PROGRAM is not set.  You probably need to select a different build tool.
CMake Error: CMAKE_CXX_COMPILER not set, after EnableLanguage
-- Configuring incomplete, errors occurred!

Tried to Install Ninja on my windows Ninja.

Config of my project under QT :

Maybe my -DCMAKE_INSTALL_PREFIX isn't ok ?
My CMAKE_MAKE_PROGRAM in QT show me a Ninja.exe, it's not ok ?
Thanks for your help :)

hskoglund

Hi, you can also try without the -G Ninja stuff, e.g.

C:\Users\flebourgeois\build-sqldrivers>qt-cmake D:\Users\flebourgeois\Documents\Q...

Cervo2paille

@hskoglund Hey, thanks i successful to do the commands. But i got again and again the same error.
The installation :

D:\Users\fabdu\Documents\build-blossom-Desktop_Qt_6_3_1_MinGW_64_bit-Debug>qt-cmake -G Ninja "D:\Users\fabdu\Documents\blossom" -DCMAKE_INSTALL_PREFIX="D:\Qt\6.3.1\mingw_64" -DMySQL_INCLUDE_DIR="D:\Program Files (x86)\MySQL\MySQL Server 5.5\include" -DMySQL_LIBRARY="D:\Program Files (x86)\MySQL\MySQL Server 5.5\lib\libmysql.lib"
-- Could NOT find WrapVulkanHeaders (missing: Vulkan_INCLUDE_DIR)
-- Configuring done
-- Generating done
CMake Warning:
  Manually-specified variables were not used by the project:

    CMAKE_TOOLCHAIN_FILE
    MySQL_INCLUDE_DIR
    MySQL_LIBRARY


-- Build files have been written to: D:/Users/fabdu/Documents/build-blossom-Desktop_Qt_6_3_1_MinGW_64_bit-Debug

D:\Users\fabdu\Documents\build-blossom-Desktop_Qt_6_3_1_MinGW_64_bit-Debug>cmake --build .
ninja: no work to do.

D:\Users\fabdu\Documents\build-blossom-Desktop_Qt_6_3_1_MinGW_64_bit-Debug>cmake --install .
-- Install configuration: "Debug"
-- Installing: D:/Qt/6.3.1/mingw_64/bin/blossom.exe

D:\Users\fabdu\Documents\build-blossom-Desktop_Qt_6_3_1_MinGW_64_bit-Debug>

The famous error :

QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QODBC QPSQL

My Path :

I think i do a mistake about the starting of this line "qt-cmake -G Ninja <qt_installation_path>\Src\qtbase\src\plugins\sqldrivers...".
What do you think about ? How to write it ?
If someone has an idea... thanks ! :)

piervalli

@Cervo2paille I haved bat file for mariadb for WIndow if you want try.

Cervo2paille

thanks yes i would like to try :)

piervalli

@Cervo2paille
That is my bat for maria db tested on 5.15.2

SET QTDIR="C:\Qt\5.15.2\Src"
SET MYSQL_INCDIR="C:\Program Files\MariaDB\MariaDB Connector C 64-bit\include"
SET MYSQL_LIBDIR="C:\Program Files\MariaDB\MariaDB Connector C 64-bit\lib"

SET PATH=%PATH%;C:\Qt\5.15.2\mingw81_64\bin;C:\Qt\Tools\mingw810_64\bin;

cd %QTDIR%\qtbase\src\plugins\sqldrivers
pause
qmake -- MYSQL_INCDIR=%MYSQL_INCDIR% MYSQL_LIBDIR=%MYSQL_LIBDIR%
pause
mingw32-make sub-mysql
pause
mingw32-make install
pause

1.Before build, clear the previous installation
2. copy libmariadb in exe directory

I hose it is useful.
The driver installed for Maria DB is "C Connector".