Can't working MYSQL database in qt (QSqlDatabase: available drivers: QSQLITE QODBC QPSQL)

[Lestev]

@JonB Hi, thanks, commands:

mkdir build-sqldrivers

cd build-sqldrivers

qt-cmake -G Ninja <qt_installation_path>/Src/qtbase/src/plugins/sqldrivers -DCMAKE_INSTALL_PREFIX=<qt_installation_path>/<platform> -DMySQL_INCLUDE_DIR="/usr/local/mysql/include" -DMySQL_LIBRARY="/usr/local/mysql/lib/libmysqlclient.<so|dylib>"

cmake --build .

cmake --install .

https://doc.qt.io/qt-6/sql-driver.html#qmysql

I want to connect to database MYSQL, but it is error bother me)...

[JonB]

@Lestev
I asked you to copy & paste the command you showed yourself issuing and going wrong in your previous post. The whole of your terminal window's input/output. You now seem to be showing something totally different and unrelated, and not even mentioning that. I don't know what you want help with. Please try to ask some question and stick with it.

[SGaist]

It's one thing to copy commands verbatim, it's another to truly understand what is going on. From what you shown, the backend was at least not installed and from the looks of it, not even built.

Did you check that you have the MySQL client library installed ?

[Lestev]

@JonB my question is simple how can i create a file libqsqlmysql.dylib if i keep getting error when calling qmake:

I follow the documentation on how to create libqsqlmysql.dylib:

the first is that I choose a folder

after i go to terminal

How can i fix this error?

[SGaist]

By following the instructions from Qt 6 as you were already explained. Instructions which makes no use of qmake as Qt 6 uses cmake as build system.
By not just copy/pasting the commands shown but doing the appropriate substitutions since there are placeholders in the instructions shown in the documentation.
By ensuring that you have the correct dependencies installed.
By checking the configure log.
By checking the build log.

[Lestev]

@SGaist So i followed documentation :

but the command gave me an error

[jsulm]

@Lestev You should really start to CAREFULLY read what others write and also try to understand what you are doing!
You are still using .<so|dylib> in your command and it should be actually apparent that you should replace it by what your platform requires (.dylib on Mac).

You also should remove "-G Ninja" if you do not have Ninja.

Also you were asked to post TEXT not pictures, but you keep posting pictures. Is there a reason for that?

[Lestev]

@jsulm wow! Thank you very much, I did this and succeeded, but the error remained, I added install_name_tool -change /usr/local/mysql-8.0.25-macos11-x86_64/lib/libmysqlclient.21.dylib /usr/local/mysql-8.0 . 25-macos11-x86_64/lib/libmysqlclient.21.dylib/Users/migellestv/Qt/6.2.3/macos/plugins/sqldrivers/libqsqlmysql.dylib

and I succeeded, but error remained:

QSqlQuery::exec: database not open
QSqlQuery::exec: database not open
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QODBC QPSQL

Why if i added install_name_tool?

[jsulm]

@Lestev Did you also do this:

cmake --build .
cmake --install .

?
https://doc.qt.io/qt-6/sql-driver.html#qmysql

[Lestev]

@jsulm said in Can't working MYSQL database in qt (QSqlDatabase: available drivers: QSQLITE QODBC QPSQL):

Did you also do this:

Yes i successed :

cmake --build .
[9/11] Linking CXX shared module plugins/sqldrivers/libqsqlmysql.dylib
ld: warning: linking against a dylib which is not safe for use in application extensions: /usr/local/mysql/lib/libmysqlclient.dylib
[11/11] Linking CXX shared module plugins/sqldrivers/libqsqlite.dylib
migellestev@Migels-MacBook-Pro build-sqldrivers % cmake --install .
-- Install configuration: "RelWithDebInfo"
-- Installing: /Users/migellestev/Qt/6.2.3/macos/lib/cmake/Qt6Sql/Qt6QMYSQLDriverPluginConfig.cmake
-- Installing: /Users/migellestev/Qt/6.2.3/macos/lib/cmake/Qt6Sql/Qt6QMYSQLDriverPluginConfigVersion.cmake
-- Installing: /Users/migellestev/Qt/6.2.3/macos/lib/cmake/Qt6Sql/Qt6QMYSQLDriverPluginConfigVersionImpl.cmake
etc

[jsulm]

@Lestev OK, then we need to debug now.
Do this on console:

• Go to the build folder of your application
• Do: export QT_DEBUG_PLUGINS=1
• Run your app from the terminal
• Copy paste the output from terminal to here

You can also set QT_DEBUG_PLUGINS in Run settings of your project in QtCreator.
https://doc.qt.io/qt-5/debug.html

[Lestev]

@jsulm Thanks, i get it, but how i can use run in terminal project?, i wrote:

migellestev@Migels-MacBook-Pro forBeginner % c++ main.cpp
main.cpp:1:10: fatal error: 'QGuiApplication' file not found
#include <QGuiApplication>
^~~~~~~~~~~~~~~~~
1 error generated.

[jsulm]

This post is deleted!

[jsulm]

@Lestev I did not ask you to build your app in the terminal, that you can still do in QtCreator.
What I asked you to do is to run the executable of your application.

[Lestev]

@jsulm hey, the terminal doesn't output anything, it only launches the application

migellestev@Migels-MacBook-Pro build-forBeginner-Clone_of_Qt_6_2_2_for_macOS-Debug % export QT_DEBUG_PLUGINS=1
migellestev@Migels-MacBook-Pro build-forBeginner-Clone_of_Qt_6_2_2_for_macOS-Debug % open forBeginner.app
migellestev@Migels-MacBook-Pro build-forBeginner-Clone_of_Qt_6_2_2_for_macOS-Debug %

Everything works, but inside qt error is keeping

[SGaist]

Don't call open, use the full path to the executable in the bundle.

[Lestev]

@SGaist hi, I think my directory is not properly defined because it should be /Users/migellestev/Qt/6.2.3/macos/plugins/sqldrivers
but directory is:
/Users/migellestev/Qt/QtDesignStudio/qt6_design_studio_reduced_version/plugins/sqldrivers

if it helps:

[Christian Ehrlicher]

Looks like you're mixing up Qt versions which is not possible. Make sure QtDesignStudio is not picked up, only your Qt6.2.2 where you also (hopefully) build your Qt mysql plugin for. Currently it looks like you created (or had by default - don't know) the plugin inside QtDesignStudio.

[Lestev]

@Christian-Ehrlicher
Thanks for your response very much,
But i verify my path and got that this path used by default, but why?

I reinstalled qt and got the same

[Christian Ehrlicher]

Don't know MacOS but on linux this means you have the other somewhere in your LD_LIBRARY_PATH or ld.so.conf. Remove it /make sure the correct path comes first.