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Connect to MYSQL failed in Qt

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qt6c++mysqlmysql server
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  • Christian EhrlicherC Christian Ehrlicher

    @ELEMENTICY said in Connect to MYSQL failed in Qt:

    it doesnt work

    This is no error description...

    E Offline
    E Offline
    ELEMENTICY
    wrote on 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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    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on 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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      • Christian EhrlicherC Offline
        Christian EhrlicherC Offline
        Christian Ehrlicher
        Lifetime Qt Champion
        wrote on 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

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        • Christian EhrlicherC Christian Ehrlicher

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

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

          This is for sure not correct.

          E Offline
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          ELEMENTICY
          wrote on last edited by ELEMENTICY
          #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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          • Christian EhrlicherC Christian Ehrlicher

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

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

            This is for sure not correct.

            E Offline
            E Offline
            ELEMENTICY
            wrote on last edited by
            #12

            @Christian-Ehrlicher

            This is for sure not correct.

            oh,how do i fix it?

            SGaistS 1 Reply Last reply
            0
            • E ELEMENTICY

              @Christian-Ehrlicher

              This is for sure not correct.

              oh,how do i fix it?

              SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on 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

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              • SGaistS SGaist

                @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
                E Offline
                ELEMENTICY
                wrote on 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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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on 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

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                  • SGaistS SGaist

                    No space no "lib" prefix.

                    It's explained in the documentation

                    E Offline
                    E Offline
                    ELEMENTICY
                    wrote on 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

                    SGaistS 1 Reply Last reply
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                    • E ELEMENTICY

                      @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
                      
                      Christian EhrlicherC Offline
                      Christian EhrlicherC Offline
                      Christian Ehrlicher
                      Lifetime Qt Champion
                      wrote on 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

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                      • E ELEMENTICY

                        @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

                        SGaistS Offline
                        SGaistS Offline
                        SGaist
                        Lifetime Qt Champion
                        wrote on 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

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                        • SGaistS SGaist

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

                          E Offline
                          E Offline
                          ELEMENTICY
                          wrote on 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

                          SGaistS 1 Reply Last reply
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                          • SGaistS SGaist

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

                            E Offline
                            E Offline
                            ELEMENTICY
                            wrote on last edited by
                            #20

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

                            SGaistS 1 Reply Last reply
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                            • E ELEMENTICY

                              @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

                              SGaistS Offline
                              SGaistS Offline
                              SGaist
                              Lifetime Qt Champion
                              wrote on 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

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                              • E ELEMENTICY

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

                                SGaistS Offline
                                SGaistS Offline
                                SGaist
                                Lifetime Qt Champion
                                wrote on 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

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                                • E Offline
                                  E Offline
                                  ELEMENTICY
                                  wrote on last edited by ELEMENTICY
                                  #23

                                  @SGaist dude,im so tired...
                                  Can you pleaseee write the 3 lines of code for me?
                                  Please... i hope after you see this message,you wont just ignore and think i never hard work on it..But im tired for just add a simple library already...
                                  It will be the BEST help for me

                                  My current code...

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

                                  Error:
                                  :-1: error: error: cannot open C:/Users/ELEMENT/Documents/PosSystem/Pos/lib/: Permission denied
                                  I opened QT Creator with Administrator,still same...

                                  I also tried..

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

                                  Error:
                                  :-1: error: no such file or directory: 'C:/Users/ELEMENT/Documents/PosSystem/Pos/lib/libmysql' clang++: error: no such file or directory: 'C:/Users/ELEMENT/Documents/PosSystem/Pos/lib/libmysql' make: *** [Makefile:79: libPos_x86_64.so] Error 1
                                  Seems like that one is the wrong way to do without adding -l

                                  appreciate it...

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                                  • E Offline
                                    E Offline
                                    ELEMENTICY
                                    wrote on last edited by
                                    #24

                                    @SGaist I removed:

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

                                    And tried only

                                    LIBS += -L"lib" -llibmysql
                                    

                                    Still error:
                                    :-1: error: error: cannot find -llibmysql

                                    1 Reply Last reply
                                    0
                                    • SGaistS Offline
                                      SGaistS Offline
                                      SGaist
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #25

                                      "Drop the lib prefix": -lmysql

                                      To repeat myself: Oracle does not provide pre-built binaries for Android.

                                      Also, @Christian-Ehrlicher already asked you several times: what exact error did you get with the QtSql module ?

                                      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
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                                      • SGaistS SGaist

                                        "Drop the lib prefix": -lmysql

                                        To repeat myself: Oracle does not provide pre-built binaries for Android.

                                        Also, @Christian-Ehrlicher already asked you several times: what exact error did you get with the QtSql module ?

                                        E Offline
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                                        ELEMENTICY
                                        wrote on last edited by ELEMENTICY
                                        #26

                                        @SGaist ok its weird,it now dont give any error.But its EXCELENT!
                                        But it unable to connect to Server
                                        My code:

                                        QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
                                                db.setHostName("localhost");
                                                db.setDatabaseName("pos");
                                                db.setUserName("root");
                                        
                                                if (!db.open()){
                                                    ui->error->setText("Oops,Unable to connect to Server!Please contact your Administrator for help.");
                                                }
                                        

                                        Includes:

                                        #include <QtSql/QSql>
                                        #include <QtSql/QSqlDatabase>
                                        #include <QtSql/QSqlDriver>
                                        #include <QtSql/QSqlQuery>
                                        

                                        and i also added sql to Qt in Profile

                                        QT       += core gui sql
                                        
                                        E 1 Reply Last reply
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                                        • E ELEMENTICY

                                          @SGaist ok its weird,it now dont give any error.But its EXCELENT!
                                          But it unable to connect to Server
                                          My code:

                                          QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
                                                  db.setHostName("localhost");
                                                  db.setDatabaseName("pos");
                                                  db.setUserName("root");
                                          
                                                  if (!db.open()){
                                                      ui->error->setText("Oops,Unable to connect to Server!Please contact your Administrator for help.");
                                                  }
                                          

                                          Includes:

                                          #include <QtSql/QSql>
                                          #include <QtSql/QSqlDatabase>
                                          #include <QtSql/QSqlDriver>
                                          #include <QtSql/QSqlQuery>
                                          

                                          and i also added sql to Qt in Profile

                                          QT       += core gui sql
                                          
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                                          ELEMENTICY
                                          wrote on last edited by
                                          #27

                                          @ELEMENTICY im sure i entered correct server info

                                          JonBJ 1 Reply Last reply
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