Qt5.11.2, QSqlDatabase, QMYSQL, Driver not loaded

[jsulm]

@SPlatten said in Qt5.11.2, QSqlDatabase, QMYSQL, Driver not loaded:

Library not loaded: /usr/local/mysql/lib/libmysqlclient.20.dylib

Do you have this lib in that location?

[SPlatten]

@jsulm , No, I've no idea what this library is or where is comes from. The path /usr/local/mysql doesn't exist.

[jsulm]

@SPlatten This is the MySQL client library which is used by Qt to access MySQL databases. You need it if you want to use MySQL.

[SPlatten]

@jsulm said in Qt5.11.2, QSqlDatabase, QMYSQL, Driver not loaded:

libmysqlclient.20.dylib

I've found what I think is the correct library on my system:

    /usr/local/Cellar/mariadb/10.2.6/lib/libmariadb.dylib

I then tried:

    sudo ln -s /usr/local/Cellar/mariadb/10.2.6/lib/libmariadb.dylib /usr/local/lib/libmysqlclient.20.dylib

Re-ran in debug and the problem has changed, looks like I'm using the wrong library now:

2018-10-11 09:15:08.331712+0100 SimonQtWidgets[1644:135071] Got keys from plugin meta data ("QPSQL7", "QPSQL")
2018-10-11 09:15:08.331726+0100 SimonQtWidgets[1644:135071] QFactoryLoader::QFactoryLoader() checking directory path "/Users/simonplatten/build-SimonQtWidgets-Desktop_Qt_5_11_2_clang_64bit-Debug/SimonQtWidgets.app/Contents/MacOS/sqldrivers" ...
2018-10-11 09:15:08.347152+0100 SimonQtWidgets[1644:135071] Cannot load library /Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib: (dlopen(/Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib, 133): Library not loaded: /usr/local/mysql/lib/libmysqlclient.20.dylib
  Referenced from: /Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib
  Reason: Incompatible library version: libqsqlmysql.dylib requires version 20.0.0 or later, but libmysqlclient.20.dylib provides version 3.0.0)
2018-10-11 09:15:08.347182+0100 SimonQtWidgets[1644:135071] QLibraryPrivate::loadPlugin failed on "/Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib" : "Cannot load library /Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib: (dlopen(/Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib, 133): Library not loaded: /usr/local/mysql/lib/libmysqlclient.20.dylib\n  Referenced from: /Users/sim
onplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib\n  Reason: Incompatible library version: libqsqlmysql.dylib requires version 20.0.0 or later, but libmysqlclient.20.dylib provides version 3.0.0)"
2018-10-11 09:15:08.347201+0100 SimonQtWidgets[1644:135071] QSqlDatabase: QMYSQL driver not loaded
2018-10-11 09:15:08.347228+0100 SimonQtWidgets[1644:135071] QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QPSQL QPSQL7

[SGaist]

Don't use ln that won't help, use install_name_tool and update the path in libqsqlmysql.dylib to match what you have on your system.

[SPlatten]

@SGaist, thank you, do you have an example? How do I achieve this?

[SGaist]

Did you read the tool's help ?

install_name_tool -change /usr/local/mysql/lib/libmysqlclient.20.dylib /path/to/mariadb/libmariadbclient.X.dylib /Users/hasan/Qt5.9.1/5.9.1/clang_64/plugins/sqldrivers/libqsqlmysql.dylib

Note that MariaDB should be a drop-in replacement however I haven't tried to "re-link" to a library that has different name (just a different compatible version number) so you may have other surprises.

[SPlatten]

@SPlatten said in Qt5.11.2, QSqlDatabase, QMYSQL, Driver not loaded:

2018-10-11 09:15:08.331712+0100 SimonQtWidgets[1644:135071] Got keys from plugin meta data ("QPSQL7", "QPSQL")
2018-10-11 09:15:08.331726+0100 SimonQtWidgets[1644:135071] QFactoryLoader::QFact

@SGaist

I'm struggling, the only libmariadbclient I can find on my entire system is:

    /usr/local/Cellar/mariadb/10.2.6/lib/libmariadbclient.a

[SGaist]

Then that's something you have to check with the brew folks.

[SPlatten]

@SGaist , I was looking for an .so library, I've now learnt that a .dylib is the mac os equivalent.

The database I'm using is MariaDB, I've just updated this using:

 brew upgrade mariadb

Then:

brew services restart mariadb

This has added:

/usr/local/Cellar/mariadb/10.3.10/lib

Containing:

-rwxr-xr-x  1 simonplatten  staff  1425020 13 Sep 05:40 libqsqlite.dylib
drwxr-xr-x  3 simonplatten  staff       96  4 Oct 13:26 libqsqlite.dylib.dSYM
-rwxr-xr-x  1 simonplatten  staff  1435972 13 Sep 05:38 libqsqlite_debug.dylib
drwxr-xr-x  3 simonplatten  staff       96  4 Oct 13:26 libqsqlite_debug.dylib.dSYM
-rwxr-xr-x  1 simonplatten  staff    79864 13 Sep 05:40 libqsqlmysql.dylib
drwxr-xr-x  3 simonplatten  staff       96  4 Oct 13:26 libqsqlmysql.dylib.dSYM
-rwxr-xr-x  1 simonplatten  staff   137448 13 Sep 05:38 libqsqlmysql_debug.dylib
drwxr-xr-x  3 simonplatten  staff       96  4 Oct 13:26 libqsqlmysql_debug.dylib.dSYM
-rwxr-xr-x  1 simonplatten  staff    88980 13 Sep 05:40 libqsqlpsql.dylib
drwxr-xr-x  3 simonplatten  staff       96  4 Oct 13:26 libqsqlpsql.dylib.dSYM
-rwxr-xr-x  1 simonplatten  staff   138612 13 Sep 05:38 libqsqlpsql_debug.dylib
drwxr-xr-x  3 simonplatten  staff       96  4 Oct 13:26 libqsqlpsql_debug.dylib.dSYM

Looking at the debug output from the Application Output:

2018-10-12 02:33:13.197110+0100 SimonQtWidgets[6965:134266] Cannot load library /Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib: (dlopen(/Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib, 133): Library not loaded: /usr/local/mysql/lib/libmysqlclient.20.dylib
  Referenced from: /Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib
  Reason: image not found)

Why is it trying to load libmysqlclient.20.dylib ?

The next line in the Application output:

2018-10-12 02:33:13.197133+0100 SimonQtWidgets[6965:134266] QLibraryPrivate::loadPlugin failed on "/Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib" : "Cannot load library /Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib: (dlopen(/Users/simonplatten/Qt/

Then:

(dlopen(/Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib, 133): Library not loaded: /usr/local/mysql/lib/libmysqlclient.20.dylib\n  Referenced from: /Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib\n  Reason: image not found)"
2018-10-12 02:33:13.1
97150+0100 SimonQtWidgets[6965:134266] QSqlDatabase: QMYSQL driver not loaded

[SPlatten]

@SPlatten said in Qt5.11.2, QSqlDatabase, QMYSQL, Driver not loaded:

libmysqlclient.20.dylib

@SGaist , I managed to progress the issue, this is what I did:

Manually create the required folder structure, from /usr/local:

sudo mkdir mysql
cd mysql
sudo mkdir lib
cd lib

Then create a symbolic link to the required library:

sudo ln -s /usr/local/lib/libmysqlclient.dylib /usr/local/mysql/lib/libmysqlclient.20.dylib

Now debugging the same project, the call to open still fails with:

2018-10-12 08:44:19.696706+0100 SimonQtWidgets[1253:117317] loaded library "/Users/simonplatten/Qt/5.11.2/clang_64/plugins/sqldrivers/libqsqlmysql.dylib"
2018-10-12 08:44:39.663805+0100 SimonQtWidgets[1253:117317] QSqlError("1130", "QMYSQL: Unable to connect", "Host '192.168.1.158' is not allowed to connect to this MariaDB server")
2018-10-12 08:44:40.409469+0100 SimonQtWidgets[1253:117317] Failed to connect.

Now resolved, the issue here was that the call to setHostName was using the host name of the system, I changed this to localhost and now everything works.

[SGaist]

That shouldn't be necessary but at least it got you going further.

As for your second error, this is your database configuration you have to inspect.

Is it a remote machine ? If not then replace the host name with localhost and try again.