Error QMYSQL Plugin on Windows

[Stelian]

When I run the code

QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QODBC QODBC3 QPSQL QPSQL7
Database is Not Connected!

[SGaist]

In Qt Creator's Run part of the Project panel, did you add the path to the MySQL dlls in the PATH environment variable ?

[Stelian]

@SGaist Let me understand.
First of all, do you mean I have to add that path "C:\Program Files (x86)\MySQL\MySQL Connector C 6.1\lib" or this path "C:\Program Files\MySQL\MySQL Server 8.0\lib"
Second of all, where do I have to add ? (see picture1 and picture2) ?

[jsulm]

@Stelian As @SGaist wrote: in QtCreator Run settings.
I think you need the MySQL connector libs (but you can simply put both).

[Stelian]

@jsulm Where do I have to add in the first picture or second ?

[jsulm]

@Stelian In the second of course as it is showing exactly what was suggested: Run settings in QtCreator.

[Stelian]

@jsulm I,ve added both C:\Program Files (x86)\MySQL\MySQL Connector C 6.1\lib" and this path "C:\Program Files\MySQL\MySQL Server 8.0\lib in Run Settings -> Run Environment -> Path, then restart Qt and run the code, Not connected.

[SGaist]

Then again, start your application with the QT_DEBUG_PLUGINS environment variable to see what is happening.

[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