Unable to use QMYSQL driver on arch linux

AgustinOrdonez

Hello, I am new to QT and I am trying to use connect to a sql database, I am using QT 6.4.3. My code works well on windows (after moving dlls) but I get the following message on my arch linux system:

QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QODBC QPSQL QMARIADB QMYSQL QSQLITE
QSqlDatabase: an instance of QCoreApplication is required for loading driver plugins
Error al conectar
QWidget: Must construct a QApplication before a QWidget

I tried following this but said commands do nothing. I also run configure -sql-mysql and it also didn't work.

My libmysqlclient.so is located at /usr/lib

File structore for Qt/6.4.3/Src/qtbase/src/plugins/sqldrivers

├── CMakeFiles
├── cmake_install.cmake
├── CMakeLists.txt
├── configure.cmake
├── CTestTestfile.cmake
├── db2
│   ├── CMakeLists.txt
│   ├── db2.json
│   ├── main.cpp
│   ├── qsql_db2.cpp
│   ├── qsql_db2_p.h
│   └── README
├── ibase
│   ├── CMakeLists.txt
│   ├── ibase.json
│   ├── main.cpp
│   ├── qsql_ibase.cpp
│   └── qsql_ibase_p.h
├── mysql
│   ├── CMakeFiles
│   │   ├── Export
│   │   │   └── 6daf95e385d7cc8ad37a0af677fcce5d
│   │   │       ├── Qt6QMYSQLDriverPluginTargets.cmake
│   │   │       └── Qt6QMYSQLDriverPluginTargets-release.cmake
│   │   ├── QMYSQLDriverPlugin_autogen.dir
│   │   │   └── AutogenInfo.json
│   │   └── QMYSQLDriverPlugin.dir
│   │       └── QMYSQLDriverPlugin_autogen
│   ├── cmake_install.cmake
│   ├── CMakeLists.txt
│   ├── CTestTestfile.cmake
│   ├── main.cpp
│   ├── mysql.json
│   ├── QMYSQLDriverPlugin.version.in
│   ├── qsql_mysql.cpp
│   ├── qsql_mysql_p.h
│   └── README
├── oci
│   ├── CMakeLists.txt
│   ├── main.cpp
│   ├── oci.json
│   ├── qsql_oci.cpp
│   ├── qsql_oci_p.h
│   └── README
├── odbc
│   ├── CMakeLists.txt
│   ├── main.cpp
│   ├── odbc.json
│   ├── qsql_odbc.cpp
│   ├── qsql_odbc_p.h
│   └── README
├── psql
│   ├── CMakeLists.txt
│   ├── main.cpp
│   ├── psql.json
│   ├── qsql_psql.cpp
│   ├── qsql_psql_p.h
│   └── README
├── qt_cmdline.cmake
├── qtsqldrivers-config.h
├── qtsqldrivers-config_p.h
├── README
└── sqlite
    ├── CMakeFiles
    │   ├── Export
    │   │   └── 6daf95e385d7cc8ad37a0af677fcce5d
    │   │       ├── Qt6QSQLiteDriverPluginTargets.cmake
    │   │       └── Qt6QSQLiteDriverPluginTargets-release.cmake
    │   ├── QSQLiteDriverPlugin_autogen.dir
    │   │   └── AutogenInfo.json
    │   └── QSQLiteDriverPlugin.dir
    │       ├── __
    │       │   └── __
    │       │       └── __
    │       │           └── 3rdparty
    │       │               └── sqlite
    │       └── QSQLiteDriverPlugin_autogen
    ├── cmake_install.cmake
    ├── CMakeLists.txt
    ├── CTestTestfile.cmake
    ├── QSQLiteDriverPlugin.version.in
    ├── qsql_sqlite.cpp
    ├── qsql_sqlite_p.h
    ├── README
    ├── smain.cpp
    └── sqlite.json

Christian Ehrlicher

As laways when debugging plugins make sure to run your app with QT_DEBUG_PLUGINS to see why the loading of the plugin fails.

AgustinOrdonez

@Christian-Ehrlicher said in Unable to use QMYSQL driver on arch linux:

QT_DEBUG_PLUGINS

Thanks for the reply, this is what I got:

qt.core.plugin.factoryloader: checking directory path "/home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers" ...
qt.core.plugin.factoryloader: looking at "/home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlodbc.so"
qt.core.plugin.loader: Found metadata in lib /home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlodbc.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QODBC"
        ]
    },
    "archlevel": 1,
    "className": "QODBCDriverPlugin",
    "debug": false,
    "version": 394240
}


qt.core.plugin.factoryloader: Got keys from plugin meta data QList("QODBC")
qt.core.plugin.factoryloader: looking at "/home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlpsql.so"
qt.core.plugin.loader: Found metadata in lib /home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlpsql.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL"
        ]
    },
    "archlevel": 1,
    "className": "QPSQLDriverPlugin",
    "debug": false,
    "version": 394240
}


qt.core.plugin.factoryloader: Got keys from plugin meta data QList("QPSQL")
qt.core.plugin.factoryloader: looking at "/home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlmysql.so"
qt.core.plugin.loader: Found metadata in lib /home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlmysql.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL",
            "QMARIADB"
        ]
    },
    "archlevel": 1,
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 394240
}


qt.core.plugin.factoryloader: Got keys from plugin meta data QList("QMYSQL", "QMARIADB")
qt.core.plugin.factoryloader: looking at "/home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlite.so"
qt.core.plugin.loader: Found metadata in lib /home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlite.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "archlevel": 1,
    "className": "QSQLiteDriverPlugin",
    "debug": false,
    "version": 394240
}


qt.core.plugin.factoryloader: Got keys from plugin meta data QList("QSQLITE")
qt.core.library: "/home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlmysql.so" cannot load: Cannot load library /home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlmysql.so: (libmysqlclient.so.21: cannot open shared object file: No such file or directory)
qt.core.plugin.loader: QLibraryPrivate::loadPlugin failed on "/home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlmysql.so" : "Cannot load library /home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlmysql.so: (libmysqlclient.so.21: cannot open shared object file: No such file or directory)"
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QODBC QPSQL QMARIADB QMYSQL QSQLITE
QSqlDatabase: an instance of QCoreApplication is required for loading driver plugins
Error al conectar
QWidget: Must construct a QApplication before a QWidget

Christian Ehrlicher

@AgustinOrdonez said in Unable to use QMYSQL driver on arch linux:

qt.core.library: "/home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlmysql.so" cannot load: Cannot load library /home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlmysql.so: (libmysqlclient.so.21: cannot open shared object file: No such file or directory)
qt.core.plugin.loader: QLibraryPrivate::loadPlugin failed on "/home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlmysql.so" : "Cannot load library /home/dioswilson1/Qt/6.4.3/gcc_64/plugins/sqldrivers/libqsqlmysql.so: (libmysqlclient.so.21: cannot open shared object file: No such file or directory)"

As you can see libmysqlclient.so.21 is missing

ChrisW67

@AgustinOrdonez said in Unable to use QMYSQL driver on arch linux:

QSqlDatabase: an instance of QCoreApplication is required for loading driver plugins

This also looks like there is something else missing in your program. Have you created and initialised a QCoreApplication (or QApplication) in your application before attempting any database operations?