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Connect to MYSQL failed in Qt

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qt6c++mysqlmysql server
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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
    0
    • 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

      1 Reply Last reply
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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

        E 2 Replies Last reply
        0
        • 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

              1 Reply Last reply
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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...

                  1 Reply Last reply
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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
                      1
                      • 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
                        E Offline
                        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
                        0
                        • 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
                          
                          E Offline
                          E Offline
                          ELEMENTICY
                          wrote on last edited by
                          #27

                          @ELEMENTICY im sure i entered correct server info

                          JonBJ 1 Reply Last reply
                          0
                          • E ELEMENTICY

                            @ELEMENTICY im sure i entered correct server info

                            JonBJ Offline
                            JonBJ Offline
                            JonB
                            wrote on last edited by JonB
                            #28

                            @ELEMENTICY
                            So your root user has no password to connect to MySQL?

                            If db.open() fails, why don't you print out db.lastError() into your error message?

                            E 1 Reply Last reply
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                            • SGaistS Offline
                              SGaistS Offline
                              SGaist
                              Lifetime Qt Champion
                              wrote on last edited by
                              #29

                              Do you have a run time warning stating that the plugin cannot be loaded ?

                              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

                                Do you have a run time warning stating that the plugin cannot be loaded ?

                                E Offline
                                E Offline
                                ELEMENTICY
                                wrote on last edited by
                                #30

                                @SGaist yes there is

                                SGaistS 1 Reply Last reply
                                0
                                • JonBJ JonB

                                  @ELEMENTICY
                                  So your root user has no password to connect to MySQL?

                                  If db.open() fails, why don't you print out db.lastError() into your error message?

                                  E Offline
                                  E Offline
                                  ELEMENTICY
                                  wrote on last edited by
                                  #31

                                  @JonB no password,only root

                                  1 Reply Last reply
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                                  • E ELEMENTICY

                                    @SGaist yes there is

                                    SGaistS Offline
                                    SGaistS Offline
                                    SGaist
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #32

                                    @ELEMENTICY said in Connect to MYSQL failed in Qt:

                                    @SGaist yes there is

                                    Then build the plugin following the instructions from the
                                    documentation.

                                    As I already noted: there's no prebuilt Oracle MySQL library for Androïd. You will have to build the MariaDB libraries and then the plugin for that platform.

                                    As a side note: if you intend for your application to access that database through internet, you should reconsider that. It's a really bad idea to put a database in front of internet.

                                    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

                                      @ELEMENTICY said in Connect to MYSQL failed in Qt:

                                      @SGaist yes there is

                                      Then build the plugin following the instructions from the
                                      documentation.

                                      As I already noted: there's no prebuilt Oracle MySQL library for Androïd. You will have to build the MariaDB libraries and then the plugin for that platform.

                                      As a side note: if you intend for your application to access that database through internet, you should reconsider that. It's a really bad idea to put a database in front of internet.

                                      E Offline
                                      E Offline
                                      ELEMENTICY
                                      wrote on last edited by
                                      #33

                                      @SGaist ok lemme try,if i understand what documentation say lol

                                      1 Reply Last reply
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