Error QMYSQL Plugin on Windows

[Stelian]

@SGaist

QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers" ...
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlite.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlite.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "archreq": 0,
    "className": "QSQLiteDriverPlugin",
    "debug": false,
    "version": 330752
}


"The plugin 'C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlite.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlited.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlited.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "archreq": 1,
    "className": "QSQLiteDriverPlugin",
    "debug": true,
    "version": 330752
}


Got keys from plugin meta data ("QSQLITE")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysql.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysql.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "archreq": 0,
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 330752
}


"The plugin 'C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysql.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysqld.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysqld.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "archreq": 1,
    "className": "QMYSQLDriverPlugin",
    "debug": true,
    "version": 330752
}


Got keys from plugin meta data ("QMYSQL3", "QMYSQL")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlodbc.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlodbc.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QODBC3",
            "QODBC"
        ]
    },
    "archreq": 0,
    "className": "QODBCDriverPlugin",
    "debug": false,
    "version": 330752
}


"The plugin 'C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlodbc.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlodbcd.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlodbcd.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QODBC3",
            "QODBC"
        ]
    },
    "archreq": 1,
    "className": "QODBCDriverPlugin",
    "debug": true,
    "version": 330752
}


Got keys from plugin meta data ("QODBC3", "QODBC")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlpsql.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlpsql.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "archreq": 0,
    "className": "QPSQLDriverPlugin",
    "debug": false,
    "version": 330752
}


"The plugin 'C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlpsql.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlpsqld.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlpsqld.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "archreq": 1,
    "className": "QPSQLDriverPlugin",
    "debug": true,
    "version": 330752
}


Got keys from plugin meta data ("QPSQL7", "QPSQL")
QFactoryLoader::QFactoryLoader() checking directory path "E:/Qt Creator/build-sql_console_test-Desktop_Qt_5_12_1_MinGW_64_bit-Debug/debug/sqldrivers" ...
Cannot load library C:\Qt\Qt5.12.1\5.12.1\mingw73_64\plugins\sqldrivers\qsqlmysqld.dll: The specified module could not be found.
QLibraryPrivate::loadPlugin failed on "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysqld.dll" : "Cannot load library C:\\Qt\\Qt5.12.1\\5.12.1\\mingw73_64\\plugins\\sqldrivers\\qsqlmysqld.dll: The specified module could not be found."
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QODBC QODBC3 QPSQL QPSQL7
Database is Not Connected!

[SGaist]

Looks like you only built the plugin for release and not for debug and you are running a debug build of your application.

[Stelian]

@SGaist I do not know if I built the plugin for release and not for debug, but if you say that I did, ok, you are the champion.
Tell me what I have to do next.

[Stelian]

@SGaist Believe me, I don't know how to build a plugin in release mode or in debug mode, to my shame.
If I did that, I did it unconsciously.

[SGaist]

Add -debug to the qmake call

[Stelian]

@SGaist I've called the qmake in debug mode, run the code and again Database is Not Connected!
Then again, I have start the application with the QT_DEBUG_PLUGINS environment variable and I get the next message

QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers" ...
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlite.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlite.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "archreq": 0,
    "className": "QSQLiteDriverPlugin",
    "debug": false,
    "version": 330752
}


"The plugin 'C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlite.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlited.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlited.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "archreq": 1,
    "className": "QSQLiteDriverPlugin",
    "debug": true,
    "version": 330752
}


Got keys from plugin meta data ("QSQLITE")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysql.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysql.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "archreq": 0,
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 330752
}


"The plugin 'C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysql.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysqld.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysqld.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "archreq": 1,
    "className": "QMYSQLDriverPlugin",
    "debug": true,
    "version": 330752
}


Got keys from plugin meta data ("QMYSQL3", "QMYSQL")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlodbc.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlodbc.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QODBC3",
            "QODBC"
        ]
    },
    "archreq": 0,
    "className": "QODBCDriverPlugin",
    "debug": false,
    "version": 330752
}


"The plugin 'C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlodbc.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlodbcd.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlodbcd.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QODBC3",
            "QODBC"
        ]
    },
    "archreq": 1,
    "className": "QODBCDriverPlugin",
    "debug": true,
    "version": 330752
}


Got keys from plugin meta data ("QODBC3", "QODBC")
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlpsql.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlpsql.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "archreq": 0,
    "className": "QPSQLDriverPlugin",
    "debug": false,
    "version": 330752
}


"The plugin 'C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlpsql.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlpsqld.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlpsqld.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "archreq": 1,
    "className": "QPSQLDriverPlugin",
    "debug": true,
    "version": 330752
}

Got keys from plugin meta data ("QPSQL7", "QPSQL")
QFactoryLoader::QFactoryLoader() checking directory path "E:/Qt Creator/build-sql_console_test-Desktop_Qt_5_12_1_MinGW_64_bit-Debug/debug/sqldrivers" ...
Cannot load library C:\Qt\Qt5.12.1\5.12.1\mingw73_64\plugins\sqldrivers\qsqlmysqld.dll: The specified module could not be found.
QLibraryPrivate::loadPlugin failed on "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysqld.dll" : "Cannot load library C:\\Qt\\Qt5.12.1\\5.12.1\\mingw73_64\\plugins\\sqldrivers\\qsqlmysqld.dll: The specified module could not be found."
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QODBC QODBC3 QPSQL QPSQL7
Database is Not Connected!

[JonB]

@Stelian

Cannot load library C:\Qt\Qt5.12.1\5.12.1\mingw73_64\plugins\sqldrivers\qsqlmysqld.dll: The specified module could not be found.

Does the exact file specified by that path actually exist, or not? (Note that the file mentioned, qsqlmysqld.dll, has a d just before the ., presumably indicating it's a debug build; this is not the same as if it were qsqlmysql.dll.)

[Stelian]

@JonB Thank you for reply!
I apologize for answering late, but that file is right in that location:

C:\Qt\Qt5.12.1\5.12.1\mingw73_64\plugins\sqldrivers\qsqlmysqld.dll

See the print screen.

[SGaist]

To reduce the output, can you move out of that folder all .dll files that are not related to MySQL ?

[Stelian]

@SGaist I removed the non-MySQL files
Here is the output

QFactoryLoader::QFactoryLoader() checking directory path "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers" ...
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysql.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysql.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "archreq": 0,
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 330752
}


"The plugin 'C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysql.dll' uses incompatible Qt library. (Cannot mix debug and release libraries.)"
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysqld.dll"
Found metadata in lib C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysqld.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "archreq": 1,
    "className": "QMYSQLDriverPlugin",
    "debug": true,
    "version": 330752
}


Got keys from plugin meta data ("QMYSQL3", "QMYSQL")
QFactoryLoader::QFactoryLoader() checking directory path "E:/Qt Creator/build-sql_console_test-Desktop_Qt_5_12_1_MinGW_64_bit-Debug/debug/sqldrivers" ...
Cannot load library C:\Qt\Qt5.12.1\5.12.1\mingw73_64\plugins\sqldrivers\qsqlmysqld.dll: The specified module could not be found.
QLibraryPrivate::loadPlugin failed on "C:/Qt/Qt5.12.1/5.12.1/mingw73_64/plugins/sqldrivers/qsqlmysqld.dll" : "Cannot load library C:\\Qt\\Qt5.12.1\\5.12.1\\mingw73_64\\plugins\\sqldrivers\\qsqlmysqld.dll: The specified module could not be found."
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QMYSQL QMYSQL3
Database is Not Connected!

Same file qsqlmysqld.dll

[SGaist]

Where exactly are the dlls matching the library you used to build the plugin ?

[Stelian]

@SGaist The dlls I've used are C:Program Files/MYSQL/MySQL Server 8.0/lib

If you talk about other dlls please correct me

[Stelian]

@SGaist I would have to use dlls from this path C:Program Files (x86)/MySQL/MySQL Connector C 6.1/lib

[SGaist]

@Stelian said in Error QMYSQL Plugin on Windows:

C:Program Files/MYSQL/MySQL Server 8.0/lib

Then that's the one you should be having in your PATH environment variable.

One other thing you can use is Dependency Walker. Use it on your Qt MySQL plugin. Check that it can find the MySQL dll.

[Stelian]

@SGaist yes, I have that path in my path environment variable.
I have never used Dependency Walker.
What do I have to do ?

[JonB]

@Stelian
Go to http://www.dependencywalker.com/, read, and download the appropriate for your architecture. You just point it at a .exe, or in this case the .dll you are having trouble with. Look through its output window, to see whether there is another .dll which is required but cannot be found, and report back.

[Stelian]

[SGaist]

If you close the yellow branches does the MySQL dll appear as good or not ?

[Stelian]

@SGaist I don't have an option to close the yellow branches

[SGaist]

I meant: close the branches where all these warnings can be seen. Just take care to verify that you're not hiding a bigger issue while doing that.