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Connect to MYSQL failed in Qt

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qt6c++mysqlmysql server
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  • S SGaist
    6 May 2021, 15:24

    Hi,

    Based on your .pro file content, you are not linking against the MySQL library.

    By the way, are you aware of the QtSql module ?

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    ELEMENTICY
    wrote on 6 May 2021, 15:31 last edited by
    #3

    @SGaist use qtsql get even more more and more error
    So its better use official sql library
    And yea,i copy the mysql include and lib folder to the project folder
    So thats why i use that

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    • C Online
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      Christian Ehrlicher
      Lifetime Qt Champion
      wrote on 6 May 2021, 18:01 last edited by
      #4

      @ELEMENTICY said in Connect to MYSQL failed in Qt:

      And yea,i copy the mysql include and lib folder to the project folder

      But you don't link against the mysql libs in your pro file.

      What does not work with the QtSql plugin?

      Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
      Visit the Qt Academy at https://academy.qt.io/catalog

      E 1 Reply Last reply 7 May 2021, 05:52
      0
      • C Christian Ehrlicher
        6 May 2021, 18:01

        @ELEMENTICY said in Connect to MYSQL failed in Qt:

        And yea,i copy the mysql include and lib folder to the project folder

        But you don't link against the mysql libs in your pro file.

        What does not work with the QtSql plugin?

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        ELEMENTICY
        wrote on 7 May 2021, 05:52 last edited by
        #5

        @Christian-Ehrlicher i do,

        win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql
        else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld
        else:unix: LIBS += -L$$PWD/lib/libmysql
        

        And yea,use qt sql it just give like 11 error
        And if i use official mysql mysql.h,it only give 2 error which is undefine

        And yea,or i need to change my profile's lib code to this?

        win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql.lib
        else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld.lib
        else:unix: LIBS += -L$$PWD/lib/libmysql.lib
        
        C 1 Reply Last reply 7 May 2021, 11:13
        0
        • E Offline
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          ELEMENTICY
          wrote on 7 May 2021, 05:54 last edited by
          #6

          will it bcuz i use qt6+ so it doesnt work?(i mean qt sql)

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            Christian Ehrlicher
            Lifetime Qt Champion
            wrote on 7 May 2021, 06:03 last edited by
            #7

            @ELEMENTICY said in Connect to MYSQL failed in Qt:

            it doesnt work

            This is no error description...

            Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
            Visit the Qt Academy at https://academy.qt.io/catalog

            E 1 Reply Last reply 7 May 2021, 10:55
            0
            • C Christian Ehrlicher
              7 May 2021, 06:03

              @ELEMENTICY said in Connect to MYSQL failed in Qt:

              it doesnt work

              This is no error description...

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              ELEMENTICY
              wrote on 7 May 2021, 10:55 last edited by
              #8

              @Christian-Ehrlicher bcuz it give too much error,i rather use official mysql header
              Qt6 has alot of stuff doesnt exist.Like web browser
              So i rather use the official mysql header and it give less error

              These are the only error:
              error: undefined reference to 'mysql_init'

              error: undefined reference to 'mysql_real_connect'

              error: linker command failed with exit code 1 (use -v to see invocation) clang++: error: linker command failed with exit code 1 (use -v to see invocation) make: *** [Makefile:73: libPos_x86_64.so] Error 1

              Use Qt sql give like 11 error or more/less

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              • S Offline
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                SGaist
                Lifetime Qt Champion
                wrote on 7 May 2021, 10:59 last edited by
                #9

                The SQL module is supported in Qt 6. However the MySQL plugin might not be provided because Oracle changed their licensing.

                As for your build issue: -L is for giving path to search, it's -l for stating the name of the library.

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

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                • C Online
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                  Christian Ehrlicher
                  Lifetime Qt Champion
                  wrote on 7 May 2021, 11:00 last edited by
                  #10

                  So the QtSql module has no errors - please stay specific!

                  else:unix: LIBS += -L$$PWD/lib/libmysql.lib

                  This is for sure not correct.

                  Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                  Visit the Qt Academy at https://academy.qt.io/catalog

                  E 2 Replies Last reply 7 May 2021, 11:01
                  0
                  • C Christian Ehrlicher
                    7 May 2021, 11:00

                    So the QtSql module has no errors - please stay specific!

                    else:unix: LIBS += -L$$PWD/lib/libmysql.lib

                    This is for sure not correct.

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                    ELEMENTICY
                    wrote on 7 May 2021, 11:01 last edited by ELEMENTICY 5 Jul 2021, 11:02
                    #11

                    @Christian-Ehrlicher but qtsql mysql plugin doesnt provided as @SGaist said it,i tried add it by following youtube tutorial,it still doesnt.Lemme try it again and send the error here

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                    • C Christian Ehrlicher
                      7 May 2021, 11:00

                      So the QtSql module has no errors - please stay specific!

                      else:unix: LIBS += -L$$PWD/lib/libmysql.lib

                      This is for sure not correct.

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                      ELEMENTICY
                      wrote on 7 May 2021, 11:02 last edited by
                      #12

                      @Christian-Ehrlicher

                      This is for sure not correct.

                      oh,how do i fix it?

                      S 1 Reply Last reply 7 May 2021, 11:03
                      0
                      • E ELEMENTICY
                        7 May 2021, 11:02

                        @Christian-Ehrlicher

                        This is for sure not correct.

                        oh,how do i fix it?

                        S Offline
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                        SGaist
                        Lifetime Qt Champion
                        wrote on 7 May 2021, 11:03 last edited by
                        #13

                        @ELEMENTICY said in Connect to MYSQL failed in Qt:

                        @Christian-Ehrlicher

                        This is for sure not correct.

                        oh,how do i fix it?

                        Re-read my previous answer.

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

                        E 1 Reply Last reply 7 May 2021, 11:05
                        0
                        • S SGaist
                          7 May 2021, 11:03

                          @ELEMENTICY said in Connect to MYSQL failed in Qt:

                          @Christian-Ehrlicher

                          This is for sure not correct.

                          oh,how do i fix it?

                          Re-read my previous answer.

                          E Offline
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                          ELEMENTICY
                          wrote on 7 May 2021, 11:05 last edited by
                          #14

                          @SGaist so i have to make it

                          win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/ -l libmysql
                          else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/ -l libmysqld
                          else:unix: LIBS += -L$$PWD/lib/ -l libmysql
                          

                          ?

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                          • S Offline
                            S Offline
                            SGaist
                            Lifetime Qt Champion
                            wrote on 7 May 2021, 11:08 last edited by
                            #15

                            No space no "lib" prefix.

                            It's explained in the documentation

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

                            E 1 Reply Last reply 7 May 2021, 11:12
                            1
                            • S SGaist
                              7 May 2021, 11:08

                              No space no "lib" prefix.

                              It's explained in the documentation

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                              ELEMENTICY
                              wrote on 7 May 2021, 11:12 last edited by
                              #16

                              @SGaist my current profile code:

                              win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/ -llibmysql
                              else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/ -llibmysqld
                              else:unix: LIBS += -L$$PWD/lib/ -llibmysql
                              

                              documentation:

                              LIBS += -L"3rdparty/CatWhisperer/lib" -lCatWhisperer
                              

                              i got this error:
                              :-1: error: error: cannot find -llibmysql

                              proof that path exists:
                              Screenshot 2021-05-07 191143.png

                              S 1 Reply Last reply 7 May 2021, 11:14
                              0
                              • E ELEMENTICY
                                7 May 2021, 05:52

                                @Christian-Ehrlicher i do,

                                win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql
                                else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld
                                else:unix: LIBS += -L$$PWD/lib/libmysql
                                

                                And yea,use qt sql it just give like 11 error
                                And if i use official mysql mysql.h,it only give 2 error which is undefine

                                And yea,or i need to change my profile's lib code to this?

                                win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql.lib
                                else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld.lib
                                else:unix: LIBS += -L$$PWD/lib/libmysql.lib
                                
                                C Online
                                C Online
                                Christian Ehrlicher
                                Lifetime Qt Champion
                                wrote on 7 May 2021, 11:13 last edited by
                                #17

                                @ELEMENTICY said in Connect to MYSQL failed in Qt:

                                And yea,use qt sql it just give like 11 error

                                What does this mean?

                                Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                                Visit the Qt Academy at https://academy.qt.io/catalog

                                1 Reply Last reply
                                0
                                • E ELEMENTICY
                                  7 May 2021, 11:12

                                  @SGaist my current profile code:

                                  win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/ -llibmysql
                                  else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/ -llibmysqld
                                  else:unix: LIBS += -L$$PWD/lib/ -llibmysql
                                  

                                  documentation:

                                  LIBS += -L"3rdparty/CatWhisperer/lib" -lCatWhisperer
                                  

                                  i got this error:
                                  :-1: error: error: cannot find -llibmysql

                                  proof that path exists:
                                  Screenshot 2021-05-07 191143.png

                                  S Offline
                                  S Offline
                                  SGaist
                                  Lifetime Qt Champion
                                  wrote on 7 May 2021, 11:14 last edited by
                                  #18

                                  @ELEMENTICY did you read what I wrote ? No "lib" prefix.

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

                                  E 2 Replies Last reply 7 May 2021, 11:16
                                  0
                                  • S SGaist
                                    7 May 2021, 11:14

                                    @ELEMENTICY did you read what I wrote ? No "lib" prefix.

                                    E Offline
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                                    ELEMENTICY
                                    wrote on 7 May 2021, 11:16 last edited by
                                    #19

                                    @SGaist
                                    current code:

                                    win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql
                                    else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld
                                    else:unix: LIBS += -L$$PWD/lib/libmysql
                                    

                                    idk if i misunderstanded what u mean,but it still give error ;/
                                    or u mean i have to remove that -L

                                    S 1 Reply Last reply 7 May 2021, 18:43
                                    0
                                    • S SGaist
                                      7 May 2021, 11:14

                                      @ELEMENTICY did you read what I wrote ? No "lib" prefix.

                                      E Offline
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                                      ELEMENTICY
                                      wrote on 7 May 2021, 11:17 last edited by
                                      #20

                                      @SGaist and yea i dont know if its because im working on a android app,so it doesnt work

                                      S 1 Reply Last reply 7 May 2021, 18:44
                                      0
                                      • E ELEMENTICY
                                        7 May 2021, 11:16

                                        @SGaist
                                        current code:

                                        win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql
                                        else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld
                                        else:unix: LIBS += -L$$PWD/lib/libmysql
                                        

                                        idk if i misunderstanded what u mean,but it still give error ;/
                                        or u mean i have to remove that -L

                                        S Offline
                                        S Offline
                                        SGaist
                                        Lifetime Qt Champion
                                        wrote on 7 May 2021, 18:43 last edited by
                                        #21

                                        @ELEMENTICY said in Connect to MYSQL failed in Qt:

                                        @SGaist
                                        current code:

                                        win32:CONFIG(release, debug|release): LIBS += -L$$PWD/lib/libmysql
                                        else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/lib/libmysqld
                                        else:unix: LIBS += -L$$PWD/lib/libmysql
                                        

                                        idk if i misunderstanded what u mean,but it still give error ;/
                                        or u mean i have to remove that -L

                                        You have to understand what -L and -l each do. I have already explained that before. So please re-read the corresponding answers.

                                        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
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                                        • E ELEMENTICY
                                          7 May 2021, 11:17

                                          @SGaist and yea i dont know if its because im working on a android app,so it doesnt work

                                          S Offline
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                                          SGaist
                                          Lifetime Qt Champion
                                          wrote on 7 May 2021, 18:44 last edited by
                                          #22

                                          @ELEMENTICY said in Connect to MYSQL failed in Qt:

                                          @SGaist and yea i dont know if its because im working on a android app,so it doesnt work

                                          Oracle does not provide pre-built binaries for Android.

                                          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
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