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

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  • L Lestev

    Hi i'm trying solve the problem, i really hope that you can help me.

    first, i got this error:

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

    I am trying all methods how solve this problem and always got an error -->

    QMake has two modes, one mode for generating project files based on
    some heuristics, and the other for generating makefiles. Normally you
    shouldn't need to specify a mode, as makefile generation is the default
    mode for qmake, but you may use this to test qmake on an existing project

    Screenshot 2022-02-22 at 16.24.52.png

    Screenshot 2022-02-22 at 16.24.09.png

    My purpose use database MYSQL in qt, please help me

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by
    #2

    @Lestev You need to build qmysql plug-in, see https://doc.qt.io/qt-5/sql-driver.html
    Because of the license it is not delivered with Qt binaries.

    1 Reply Last reply
    0
    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #3

      Hi and welcome to devnet,

      In addition to @jsulm, you need to grab the Qt sources matching the one that you have installed. And since you are using Qt 6.2 you should follow the instructions provided in the corresponding documentation which does not use qmake at all.

      Interested in AI ? www.idiap.ch
      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

      L 1 Reply Last reply
      1
      • SGaistS SGaist

        Hi and welcome to devnet,

        In addition to @jsulm, you need to grab the Qt sources matching the one that you have installed. And since you are using Qt 6.2 you should follow the instructions provided in the corresponding documentation which does not use qmake at all.

        L Offline
        L Offline
        Lestev
        wrote on last edited by
        #4

        @SGaist thanks, but i got error Screenshot 2022-02-22 at 17.04.56.png

        JonBJ 1 Reply Last reply
        0
        • L Lestev

          @SGaist thanks, but i got error Screenshot 2022-02-22 at 17.04.56.png

          JonBJ Offline
          JonBJ Offline
          JonB
          wrote on last edited by
          #5

          @Lestev
          Whatever instructions you are following, you are not supposed to literally type:

          qt-cmake -G Ninja <qt_installation_path>/Users/...
          

          hence the error message mentioning

          no such file or directory: qt_installation_path
          

          ...

          1 Reply Last reply
          1
          • SGaistS Offline
            SGaistS Offline
            SGaist
            Lifetime Qt Champion
            wrote on last edited by
            #6

            Also, did you install cmake ? From one of your errors it seems not...

            Interested in AI ? www.idiap.ch
            Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

            L 1 Reply Last reply
            1
            • SGaistS SGaist

              Also, did you install cmake ? From one of your errors it seems not...

              L Offline
              L Offline
              Lestev
              wrote on last edited by
              #7

              @SGaist I install cmake but error: Screenshot 2022-02-22 at 19.34.02.png

              JonBJ 1 Reply Last reply
              0
              • L Lestev

                @SGaist I install cmake but error: Screenshot 2022-02-22 at 19.34.02.png

                JonBJ Offline
                JonBJ Offline
                JonB
                wrote on last edited by JonB
                #8

                @Lestev
                I think you have typed an incorrect character in the command you are trying to copy from somewhere? You have a > where I do not think you should have, maybe even a < too. Could you please

                • Copy and paste all that text here instead of a screenshot, please; and
                • Show where/what exactly it is that is telling you what to type as the command.
                L 1 Reply Last reply
                0
                • JonBJ JonB

                  @Lestev
                  I think you have typed an incorrect character in the command you are trying to copy from somewhere? You have a > where I do not think you should have, maybe even a < too. Could you please

                  • Copy and paste all that text here instead of a screenshot, please; and
                  • Show where/what exactly it is that is telling you what to type as the command.
                  L Offline
                  L Offline
                  Lestev
                  wrote on last edited by Lestev
                  #9

                  @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

                  Screenshot 2022-02-22 at 21.40.10.png

                  Screenshot 2022-02-22 at 21.40.59.png

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

                  JonBJ 1 Reply Last reply
                  0
                  • L 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

                    Screenshot 2022-02-22 at 21.40.10.png

                    Screenshot 2022-02-22 at 21.40.59.png

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

                    JonBJ Offline
                    JonBJ Offline
                    JonB
                    wrote on last edited by JonB
                    #10

                    @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.

                    L 1 Reply Last reply
                    0
                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #11

                      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 ?

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      1 Reply Last reply
                      0
                      • JonBJ 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.

                        L Offline
                        L Offline
                        Lestev
                        wrote on last edited by
                        #12

                        @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:

                        Screenshot 2022-02-22 at 22.11.26.png

                        the first is that I choose a folder
                        Screenshot 2022-02-22 at 22.12.57.png

                        after i go to terminal
                        Screenshot 2022-02-22 at 22.16.21.png
                        How can i fix this error?

                        1 Reply Last reply
                        0
                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #13

                          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.

                          Interested in AI ? www.idiap.ch
                          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                          L 1 Reply Last reply
                          3
                          • SGaistS 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.

                            L Offline
                            L Offline
                            Lestev
                            wrote on last edited by
                            #14

                            @SGaist So i followed documentation :
                            Screenshot 2022-02-23 at 10.00.44.png

                            Screenshot 2022-02-23 at 10.00.16.png

                            but the command gave me an error

                            jsulmJ 1 Reply Last reply
                            0
                            • L Lestev

                              @SGaist So i followed documentation :
                              Screenshot 2022-02-23 at 10.00.44.png

                              Screenshot 2022-02-23 at 10.00.16.png

                              but the command gave me an error

                              jsulmJ Offline
                              jsulmJ Offline
                              jsulm
                              Lifetime Qt Champion
                              wrote on last edited by
                              #15

                              @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?

                              L 1 Reply Last reply
                              1
                              • jsulmJ 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?

                                L Offline
                                L Offline
                                Lestev
                                wrote on last edited by
                                #16

                                @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?

                                jsulmJ 1 Reply Last reply
                                0
                                • L 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?

                                  jsulmJ Offline
                                  jsulmJ Offline
                                  jsulm
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #17

                                  @Lestev Did you also do this:

                                  cmake --build .
                                  cmake --install .
                                  

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

                                  L 1 Reply Last reply
                                  0
                                  • jsulmJ jsulm

                                    @Lestev Did you also do this:

                                    cmake --build .
                                    cmake --install .
                                    

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

                                    L Offline
                                    L Offline
                                    Lestev
                                    wrote on last edited by
                                    #18

                                    @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

                                    jsulmJ 1 Reply Last reply
                                    0
                                    • L 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

                                      jsulmJ Offline
                                      jsulmJ Offline
                                      jsulm
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #19

                                      @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

                                      L 1 Reply Last reply
                                      0
                                      • jsulmJ 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

                                        L Offline
                                        L Offline
                                        Lestev
                                        wrote on last edited by Lestev
                                        #20

                                        @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.

                                        jsulmJ 2 Replies Last reply
                                        0
                                        • L 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.

                                          jsulmJ Offline
                                          jsulmJ Offline
                                          jsulm
                                          Lifetime Qt Champion
                                          wrote on last edited by
                                          #21
                                          This post is deleted!
                                          1 Reply Last reply
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