Qt Ubuntu QSqlDatabase: QMYSQL driver not loaded

magalss

i use documentation
https://forum.qt.io/topic/59449/qsqldatabase-qmysql-driver-not-loaded-build-mysql-plugin/2
http://doc.qt.io/qt-5/sql-driver.html
alt text

but i have exception when open connect, why?

"2018-01-18 02:04:52.567 WRN default: QSqlDatabase: QMYSQL driver not loaded
2018-01-18 02:04:52.567 WRN default: QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QPSQL QPSQL7"

jsulm

@magalss Can you post the output of this command:

ldd /usr/lib/i386-linux-gnu/qt5/plugins/sqldrivers/libqsqlmysql.sh

magalss

jsulm

@magalss It looks like libqsqlmysql.so takes libmysqlclient.so from /usr/lib/... not from /usr/local/lib.
If you want to use the one from /usr/local/lib you will need to add the path to LD_LIBRARY_PATH
You can try to set QT_DEBUG_PLUGINS=1 before starting your app - you then should see some debug output which can help to find the issue (see http://doc.qt.io/qt-5/debug.html).

magalss

@jsulm said in Qt Ubuntu QSqlDatabase: QMYSQL driver not loaded:

LD_LIBRARY_PATH

QFactoryLoader::QFactoryLoader() checking directory path "/home/max/Qt/5.5/gcc/plugins/platforms" ...
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/platforms/libqlinuxfb.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/platforms/libqlinuxfb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "linuxfb"
        ]
    },
    "className": "QLinuxFbIntegrationPlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("linuxfb")
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/platforms/libqminimal.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/platforms/libqminimal.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "minimal"
        ]
    },
    "className": "QMinimalIntegrationPlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("minimal")
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/platforms/libqoffscreen.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/platforms/libqoffscreen.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "offscreen"
        ]
    },
    "className": "QOffscreenIntegrationPlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("offscreen")
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/platforms/libqxcb.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/platforms/libqxcb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "xcb"
        ]
    },
    "className": "QXcbIntegrationPlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("xcb")
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/ProjectTerminal/build-PaymentTerminal-Desktop-Debug/platforms" ...
loaded library "/home/max/Qt/5.5/gcc/plugins/platforms/libqxcb.so"
loaded library "Xcursor"
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/Qt/5.5/gcc/plugins/xcbglintegrations" ...
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/xcbglintegrations/libqxcb-glx-integration.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/xcbglintegrations/libqxcb-glx-integration.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.Xcb.QXcbGlIntegrationFactoryInterface.5.5",
    "MetaData": {
        "Keys": [
            "xcb_glx"
        ]
    },
    "className": "QXcbGlxIntegrationPlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("xcb_glx")
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/ProjectTerminal/build-PaymentTerminal-Desktop-Debug/xcbglintegrations" ...
loaded library "/home/max/Qt/5.5/gcc/plugins/xcbglintegrations/libqxcb-glx-integration.so"
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/Qt/5.5/gcc/plugins/platformthemes" ...
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/platformthemes/libqgtk2.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/platformthemes/libqgtk2.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformThemeFactoryInterface.5.1",
    "MetaData": {
        "Keys": [
            "gtk2"
        ]
    },
    "className": "QGtk2ThemePlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("gtk2")
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/ProjectTerminal/build-PaymentTerminal-Desktop-Debug/platformthemes" ...
loaded library "/home/max/Qt/5.5/gcc/plugins/platformthemes/libqgtk2.so"
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/Qt/5.5/gcc/plugins/platforminputcontexts" ...
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/platforminputcontexts/libcomposeplatforminputcontextplugin.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/platforminputcontexts/libcomposeplatforminputcontextplugin.so, metadata=
{
    "IID": "org.qt-project.Qt.QPlatformInputContextFactoryInterface.5.1",
    "MetaData": {
        "Keys": [
            "compose"
        ]
    },
    "className": "QComposePlatformInputContextPlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("compose")
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/platforminputcontexts/libibusplatforminputcontextplugin.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/platforminputcontexts/libibusplatforminputcontextplugin.so, metadata=
{
    "IID": "org.qt-project.Qt.QPlatformInputContextFactoryInterface.5.1",
    "MetaData": {
        "Keys": [
            "ibus"
        ]
    },
    "className": "QIbusPlatformInputContextPlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("ibus")
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/ProjectTerminal/build-PaymentTerminal-Desktop-Debug/platforminputcontexts" ...
loaded library "/home/max/Qt/5.5/gcc/plugins/platforminputcontexts/libibusplatforminputcontextplugin.so"
loaded library "libdbus-1"
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/Qt/5.5/gcc/plugins/styles" ...
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/ProjectTerminal/build-PaymentTerminal-Desktop-Debug/styles" ...
loaded library "gtk-x11-2.0"
loaded library "gnomeui-2"
loaded library "gnomevfs-2"
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/Qt/5.5/gcc/plugins/iconengines" ...
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/iconengines/libqsvgicon.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/iconengines/libqsvgicon.so, metadata=
{
    "IID": "org.qt-project.Qt.QIconEngineFactoryInterface",
    "MetaData": {
        "Keys": [
            "svg",
            "svgz",
            "svg.gz"
        ]
    },
    "className": "QSvgIconPlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("svg", "svgz", "svg.gz")
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/ProjectTerminal/build-PaymentTerminal-Desktop-Debug/iconengines" ...

magalss

my code

#include "mainwindow.h"
#include <QApplication>
#include <QFile>
#include <QDir>
#include <QScopedPointer>
#include <QTextStream>
#include <QDateTime>
#include <QLoggingCategory>
#include <QSqlDatabase>
#include <QSqlError>
#include <cstdio>
#include "LoggingCategories.h"
#include <QSqlQuery>

QScopedPointer<QFile>   m_logFile;

void messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg);

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

    QApplication a(argc, argv);
    QString atrs = QString();
    MainWindow w;
    QObject::connect(&a, SIGNAL(aboutToQuit()),&w, SLOT(closing()));

    //qDebug()<<QSqlDatabase::drivers();
    for(int i=1; i< argc; i++)
    {
        atrs += argv[i];
        atrs += " ";
    }

    /// TODO: settings logs
    if(!QDir("logs").exists())
    {
       QDir().mkdir("logs");
    }

    m_logFile.reset(new QFile("logs/" +QDateTime::currentDateTime().toString("yyyy-MM-dd") + ".txt"));
    m_logFile.data()->open(QFile::Append | QFile::Text);
    qInstallMessageHandler(messageHandler);

    qInfo(logInfo()) << " ";
    qInfo(logInfo()) << "-------------------------------------------";
    qInfo(logInfo()) << "Start Program with args:" + atrs;

    /// TODO: settings DataBase
    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
    db.setHostName("localhost");
    db.setPort(3306);
    db.setUserName("*******");
    db.setPassword("********");
    db.setConnectOptions();


    if(db.open())
    {
        qInfo(logInfo()) << "Connect database";
    }
    else
    {
        qCritical(logCritical()) << "Error: can't open database";
    }



    w.show();

    return a.exec();
}

void messageHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg)
{

    QTextStream out(m_logFile.data());
    out << QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss.zzz ");

    switch (type)
    {
        case QtInfoMsg:     out << "INF "; break;
        case QtDebugMsg:    out << "DBG "; break;
        case QtWarningMsg:  out << "WRN "; break;
        case QtCriticalMsg: out << "CRT "; break;
        case QtFatalMsg:    out << "FTL "; break;
    }

    out << context.category << ": "
        << msg << endl;
    out.flush();
}

jsulm

@magalss I don't see Qt trying to load the MySQL plug-in - is this really the whole output?

magalss

@jsulm said in Qt Ubuntu QSqlDatabase: QMYSQL driver not loaded:

@magalss I don't see Qt trying to load the MySQL plug-in - is this really the whole output?

yeah,
i set settings:
alt text

pro file:

#-------------------------------------------------
#
# Project created by QtCreator 2017-12-05T17:31:01
#
#-------------------------------------------------

QT       += core gui sql

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = PaymentTerminal
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp \
    LoggingCategories.cpp

HEADERS  += mainwindow.h \
    LoggingCategories.h

FORMS    += mainwindow.ui

magalss

i found mysql information plugin

Got keys from plugin meta data ("QSQLITE")
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/sqldrivers/libqsqlmysql.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/sqldrivers/libqsqlmysql.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("QMYSQL3", "QMYSQL")
QFactoryLoader::QFactoryLoader() looking at "/home/max/Qt/5.5/gcc/plugins/sqldrivers/libqsqlpsql.so"
Found metadata in lib /home/max/Qt/5.5/gcc/plugins/sqldrivers/libqsqlpsql.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "className": "QPSQLDriverPlugin",
    "debug": false,
    "version": 328961
}


Got keys from plugin meta data ("QPSQL7", "QPSQL")
QFactoryLoader::QFactoryLoader() checking directory path "/home/max/ProjectTerminal/build-PaymentTerminal-Desktop-Debug/sqldrivers" ...

magalss

this create makefile solved problem

/home/max/Qt/5.5/gcc/bin/qmake "LIBS+=-L/usr/lib/i386-linux-gnu -lmysqlclient_r" mysql.pro