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Selecting data from mysql using qt?

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  • D Offline
    D Offline
    Dii
    wrote on last edited by
    #117

    ok, then
    sudo gedit /opt/lamp/etc/my.cnf

    look for the socket = something line

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    • L Offline
      L Offline
      lyuts
      wrote on last edited by
      #118

      ¤ Dii ¤, maybe this would be easier?

      @sudo find /opt/lampp -name my.cnf -type f | xargs grep -n socket@

      I'm a rebel in the S.D.G.

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      • D Offline
        D Offline
        doforumda
        wrote on last edited by
        #119

        Dii: i use this command sudo gedit /opt/lamp/etc/my.cnf but unfortunately the file is empty. there is nothing in it.

        lyut: your command sudo find /opt/lampp -name my.cnf -type f | xargs grep -n socket

        displays this
        @
        root@zafar-laptop:/# sudo find /opt/lampp -name my.cnf -type f | xargs
        /opt/lampp/etc/my.cnf
        @

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        • D Offline
          D Offline
          doforumda
          wrote on last edited by
          #120

          sorry wait

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          • D Offline
            D Offline
            Dii
            wrote on last edited by
            #121

            lyuts: yes it should be easier...

            doforumda: i misstyped the command, try this:
            sudo gedit /opt/lampp/etc/my.cnf

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            • D Offline
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              doforumda
              wrote on last edited by
              #122

              lyut: your command sudo find /opt/lampp -name my.cnf -type f | xargs grep -n socket actually displays this. above one was wrong because i use the wrong command

              @
              root@zafar-laptop:/# sudo find /opt/lampp -name my.cnf -type f | xargs grep -n socket
              21:socket = /opt/lampp/var/mysql/mysql.sock
              28:socket = /opt/lampp/var/mysql/mysql.sock
              44:# All interaction with mysqld must be made via Unix sockets or named pipes.
              @

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              • D Offline
                D Offline
                doforumda
                wrote on last edited by
                #123

                lyut: sudo gedit /opt/lampp/etc/my.cnf this command does open my.cnf and it also have

                socket = /opt/lampp/var/mysql/mysql.sock

                in two lines means there are two entries for socket in my.cnf

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                • L Offline
                  L Offline
                  lyuts
                  wrote on last edited by
                  #124

                  I think this is rather rough solution, but worth trying:

                  @sudo mkdir -p /var/run/mysqld
                  sudo ln -s /opt/lampp/var/mysql/mysql.sock /var/run/mysqld/mysqld.sock@

                  I'm a rebel in the S.D.G.

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                  • D Offline
                    D Offline
                    doforumda
                    wrote on last edited by
                    #125

                    so what next i think here the path for socket is correct because i have one mysql.sock file in that exactly same directory

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                    • D Offline
                      D Offline
                      doforumda
                      wrote on last edited by
                      #126

                      you mean i should create a dir at opt/lampp/var/run/mysqld ????

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                      • D Offline
                        D Offline
                        doforumda
                        wrote on last edited by
                        #127

                        millions of thanks to both of you TYUT and Dii. it works. one more question can please tell me what does this command do
                        @
                        sudo ln -s /opt/lampp/var/mysql/mysql.sock /var/run/mysqld/mysqld.sock
                        @

                        and also if i want to install everything from scratch then once i have to use this command to make it work?

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                        • D Offline
                          D Offline
                          Dii
                          wrote on last edited by
                          #128

                          doforumda: the problem was ~small... the Qt mysql driver looks for the socket file (the connection to mysql) in the default location (var/run/mysqld/mysqld.sock), though you had it somewhere else, because your lampp package changed the path.

                          The "ln -s" made a symbolic link to that, so the /var/run/mysqld/mysqld.sock point to the /opt/lampp/var/mysql/mysql.sock. This way Qt can find it. If you do a new installation, with lampp, you should do it again, if you use the regular mysql package, probably, you won't face this problem.

                          lyuts: great work, we deserve these points :)

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                          • L Offline
                            L Offline
                            lyuts
                            wrote on last edited by
                            #129

                            I think our solution is rough enough, but at least it works. I think the best solution is to set the socket parameter in my.cnf to /var/run/mysqld/mysqld.sock. But it is up to you doforumda.

                            bq. millions of thanks to both of you TYUT and Dii.

                            Hey, I'm lyuts, not TYUT :)

                            doforumda and ¤ Dii ¤, my congratulations, we did it.

                            I'm a rebel in the S.D.G.

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                            • D Offline
                              D Offline
                              Dii
                              wrote on last edited by
                              #130

                              lyuts: I think that's the best solution, if he is changing the socket parameter of mysql probably he will screw up some other components in his LAMPP configuration. I don't recommend that.

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                              • L Offline
                                L Offline
                                lyuts
                                wrote on last edited by
                                #131

                                I don't know what's going on within LAMPP and you might be right. It's just creating this symlink looks more like a workaround.

                                I'm a rebel in the S.D.G.

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                                • D Offline
                                  D Offline
                                  doforumda
                                  wrote on last edited by
                                  #132

                                  [quote author="lyuts" date="1286886793"]I think our solution is rough enough, but at least it works. I think the best solution is to set the socket parameter in my.cnf to /var/run/mysqld/mysqld.sock. But it is up to you doforumda.

                                  bq. millions of thanks to both of you TYUT and Dii.

                                  Hey, I'm lyuts, not TYUT :)

                                  doforumda and ¤ Dii ¤, my congratulations, we did it.[/quote]

                                  sorry I wrote your name wrong

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                                  • ? This user is from outside of this forum
                                    ? This user is from outside of this forum
                                    Guest
                                    wrote on last edited by
                                    #133

                                    with 131 replies, I think this must be the longest threaded discussion in devnet forum so far !!!
                                    congrats to you guys for sticking till the end and solving it :)

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                                    • D Offline
                                      D Offline
                                      doforumda
                                      wrote on last edited by
                                      #134

                                      hi
                                      i have got the same problem again after restarting my system.
                                      when i execute code it again fails to connect. it returns this problem.
                                      @
                                      Starting /home/zafar/c++/insertquery-build-desktop/insertquery...
                                      DB could be opened QSqlError(2002, "QMYSQL: Unable to connect", "Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)")
                                      /home/zafar/c++/insertquery-build-desktop/insertquery exited with code 0
                                      @

                                      i ran this command
                                      @
                                      sudo ln -s /opt/lampp/var/mysql/mysql.sock /var/run/mysqld/mysqld.sock
                                      @
                                      but this displays this error
                                      @
                                      ln: creating symbolic link `/var/run/mysqld/mysqld.sock': No such file or directory
                                      @
                                      i have already created this directory while lyut and Dii were solving this problem. at that time when i ran this command it worked really perfect but now it is not working.
                                      Please help

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                                      • D Offline
                                        D Offline
                                        Dii
                                        wrote on last edited by
                                        #135

                                        Welcome back :)

                                        Let's check to existence of those sock files...

                                        sudo ls -l /opt/lampp/var/mysql/mysql.sock

                                        sudo ls -l /var/run/mysqld/mysqld.sock

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                                        • D Offline
                                          D Offline
                                          doforumda
                                          wrote on last edited by
                                          #136

                                          well mysql.sock is there
                                          but there is no such thing in mysqld. i mean there is no mysqld.sock file in mysqld folder

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