Qt 5.10.0 MySQL drivers fails to compile

[jsulm]

@Maxx-Dovahkiin said in Qt 5.10.0 MySQL drivers fails to compile:

/opt/Qt/Qt5.10.0/5.10.0/gcc_64/bin/qmake "INCLUDEPATH+=/usr/include/mysql" "LIBS+=-L/usr/lib64/mysql" mysql.pro

I'm not sure it is necessary to pass the include/libs path to qmake as both headers and libs are in system directories (/usr/include, usr/lib64).

[Maxx Dovahkiin]

@jsulm Well actually i tried both ways with the path and without but still ended in the same place.

qsql_mysql.cpp:235:9: error: ‘my_bool’ does not name a type; did you mean ‘_Bool’?

Don't know if this is some dependency issue or what... I even tried to change the c++ standard to C++11 in Makefile but didn't helped.

[Maxx Dovahkiin]

Seriously this is getting very very weird. Searching all over the internet like a madman for days now and nowhere does this error comes up and i have literally no clue as to what needs to be done. Whether am i missing very specific packages or done something wrong ?

Literally tried all solutions out there still ending up in the same error.

[jsulm]

@Maxx-Dovahkiin Can't you simply create libmysqlclient.so.18 symlink pointing to libmysqlclient.so.21?

[Maxx Dovahkiin]

@jsulm Yes did that many a times but somehow that didn't worked...

ln -s libmysqlclient.so.21.0.4 libmysqlclient.so.18

But Qt doesn't seem to agree...

QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QPSQL QPSQL7
Database Cannot Be Opened

[SGaist]

Hi,

Run your application with the QT_DEBUG_PLUGINS environment variable set to one to see what happens with the MySQL plugin.

[Maxx Dovahkiin]

@SGaist said in Qt 5.10.0 MySQL drivers fails to compile:

QT_DEBUG_PLUGINS

Ok i have set QT_DEBUG_PLUGINS in Run Environment to 1. Now the error is a bit different.

An error occurred while opening the connection: Authentication plugin 'caching_sha2_password' cannot be loaded: /usr/lib64/mysql/plugin/caching_sha2_password.so: cannot open shared object file: No such file or directory QMYSQL: Unable to connect

Application output pane shows this

QFactoryLoader::QFactoryLoader() looking at "/opt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/libqsqlmysql.so"
Found metadata in lib /opt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/libqsqlmysql.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL"
        ]
    },
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 330240
}


Got keys from plugin meta data ("QMYSQL3", "QMYSQL")
QFactoryLoader::QFactoryLoader() looking at "/opt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/libqsqlpsql.so"
Found metadata in lib /opt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/libqsqlpsql.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "className": "QPSQLDriverPlugin",
    "debug": false,
    "version": 330240
}


Got keys from plugin meta data ("QPSQL7", "QPSQL")
QFactoryLoader::QFactoryLoader() checking directory path "/var/local/Reader/build-Reader-Desktop_Qt_5_10_0_GCC_64bit-Debug/sqldrivers" ...
loaded library "/opt/Qt5.10.0/5.10.0/gcc_64/plugins/sqldrivers/libqsqlmysql.so"
Database Cannot Be Opened
loaded library "/opt/Qt5.10.0/5.10.0/gcc_64/plugins/iconengines/libqsvgicon.so"

[SGaist]

Did you check that you have that caching_sha2_password.so library ?

[Maxx Dovahkiin]

So finally the solution have been found. I had to do a Fresh Install of Fedora 27 and this time installed the previous MySQL version which was there in Fedora 25

dnf install https://dev.mysql.com/get/mysql57-community-release-fc25-9.noarch.rpm
dnf install mysql-community-server

Also installed all other dependencies. After that installed Qt 5.10.0 from the offline package as usual. Then recompiled the sqldrivers and it just went smoothly without showing any errors at all.

So i guess MySQL 8.0 is incompatible with Qt as of now.

[sm.sabat]

You have to set MySQL Server to use legacy authentication (during the installation or just reconfigure it later). You have to do so even for MySQL Workbench to work.

Edit: the solution doesn't work after all... sorry. So I'm now with the same problem - my Qt app doesn't work with MySQL at all... maybe the legacy libmysql.dll is needed?

Edit 2: a workaround I've used is to use ODBC driver to connect to MySQL database.