QTDriver not Load

jsulm

@lucaynnofrota said in QTDriver not Load:

What is "sub" in documentation?

What sub do you mean?

lucaynnofrota

Thanks for reply
http://doc.qt.io/qt-5/sql-driver.html
Exist this code in documentation

cd $QTDIR/qtbase/src/plugins/sqldrivers
qmake -- MYSQL_PREFIX=/usr/local
make sub-mysql

What is this "sub"?

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