QTDriver not Load

[jsulm]

@lucaynnofrota It is a build target. Open the generated Makefile and search for sub-mysql there.

[kmyukie]

Hello, I have the same problem as @lucaynnofrota. I think I might be using the wrong commands to compile the MySQL plugin, although I have tried to follow the documentation. I'm on a Mac.
I've inputted in Terminal:

cd /Volumes/Potato/apps/5.11.2/Src/qtbase/src/plugins/sqldrivers
qmake -- MYSQL_PREFIX=/usr/local/mysql
make sub-mysql

In which "apps" is the Qt folder I've accidentally renamed.
But whenever I try to execute this:

#include <iostream>
#include <QtSql>
#include <QtCore>
#include <QString>
#include <QCoreApplication>
using namespace std;

int main(int argc,char *argv[])
{
       QCoreApplication a(argc,argv);

       QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
       bool ok = db.open();
       if(ok) cout << "OK!\n";
       qDebug() << db.lastError();
}

I get :

QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QPSQL QPSQL7
QSqlError("", "Driver not loaded", "Driver not loaded")

My .pro file is:

TEMPLATE = app
CONFIG += console c++11
CONFIG -= app_bundle
CONFIG += qt
QT += sql gui
SOURCES += \
        main.cpp

What am I doing wrong?
Thanks!

[SGaist]

Hi,

Add the QT_DEBUG_PLUGINS environment variable in the Run part of the Project panel. You'll have more information about why the plugins doesn't load. A wild guess would be that the application can't find the MySQL dlls at run time.

[kmyukie]

Thanks for replying!
I've tried to set QT_DEBUG_PLUGINS to 1, and the output is:

cd /; /Volumes/Potato/apps/Qt\ Creator.app/Contents/MacOS/../Resources/qtcreator_process_stub run /var/folders/sv/76q4jsns75g48tkx3b4g__3c0000gn/T/QtCreator.kFAuXu/stub-socket Press\ \<RETURN\>\ to\ close\ this\ window... /Users/yukie/build-testsqlite-Desktop_Qt_5_11_2_clang_64bit-Release /var/folders/sv/76q4jsns75g48tkx3b4g__3c0000gn/T/QtCreator.KiilXk 23590 /Users/yukie/build-testsqlite-Desktop_Qt_5_11_2_clang_64bit-Release/testsqlite
QFactoryLoader::QFactoryLoader() checking directory path "/Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers" ...
QFactoryLoader::QFactoryLoader() looking at "/Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlite.dylib"
Found metadata in lib /Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlite.dylib, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "className": "QSQLiteDriverPlugin",
    "debug": false,
    "version": 330498
}


Got keys from plugin meta data ("QSQLITE")
QFactoryLoader::QFactoryLoader() looking at "/Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlite_debug.dylib"
Found metadata in lib /Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlite_debug.dylib, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "className": "QSQLiteDriverPlugin",
    "debug": true,
    "version": 330498
}


Got keys from plugin meta data ("QSQLITE")
QFactoryLoader::QFactoryLoader() looking at "/Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib"
Found metadata in lib /Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 330498
}


Got keys from plugin meta data ("QMYSQL3", "QMYSQL")
QFactoryLoader::QFactoryLoader() looking at "/Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql_debug.dylib"
Found metadata in lib /Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql_debug.dylib, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "className": "QMYSQLDriverPlugin",
    "debug": true,
    "version": 330498
}


Got keys from plugin meta data ("QMYSQL3", "QMYSQL")
QFactoryLoader::QFactoryLoader() looking at "/Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib"
Found metadata in lib /Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "className": "QPSQLDriverPlugin",
    "debug": false,
    "version": 330498
}


Got keys from plugin meta data ("QPSQL7", "QPSQL")
QFactoryLoader::QFactoryLoader() looking at "/Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlpsql_debug.dylib"
Found metadata in lib /Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlpsql_debug.dylib, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "className": "QPSQLDriverPlugin",
    "debug": true,
    "version": 330498
}


Got keys from plugin meta data ("QPSQL7", "QPSQL")
QFactoryLoader::QFactoryLoader() checking directory path "/Users/yukie/build-testsqlite-Desktop_Qt_5_11_2_clang_64bit-Release/sqldrivers" ...
Cannot load library /Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib: (dlopen(/Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib, 133): Library not loaded: /usr/local/mysql/lib/libmysqlclient.20.dylib
  Referenced from: /Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib
  Reason: image not found)
QLibraryPrivate::loadPlugin failed on "/Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib" : "Cannot load library /Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib: (dlopen(/Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib, 133): Library not loaded: /usr/local/mysql/lib/libmysqlclient.20.dylib\n  Referenced from: /Volumes/Potato/apps/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib\n  Reason: image not found)"
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QPSQL QPSQL7
QSqlError("", "Driver not loaded", "Driver not loaded")
QSqlQuery::prepare: database not open
QSqlQuery::prepare: database not open
QSqlQuery::prepare: database not open

[SGaist]

I didn't realise that you are working on macOS. This thread is for Windows.

As for your issue, it has already been answered many times already on this forum. Please search it.

[jsulm]

@kmyukie Didn't you forgot "make install"?

[ankurboruah]

@jsulm I had the same issue as @lucaynnofrota where the qtsqldrivers-config.pri file was not found. Any idea where I can find the file?

[SGaist]

@ankurboruah This file is created when you configure Qt.

[ankurboruah]

@SGaist Thanks for your reply. I came to the same conclusion as well. Going through with configuring Qt. Hopefully no errors pop up during that.

[SGaist]

Which version of Qt are you trying to build the driver for ?

[lucaynnofrota]

The problem with MySQL I could not solve.
I tried using Postgres and I had no problem. Shortly afterwards I realized that I was making a Mistake, the latest versions of MySQL are for 64bit and the version I was using from 32bit qt