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Selecting data from mysql using qt?

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    doforumda
    wrote on last edited by
    #79

    i changed db.lastError().text(); and place it after db.open()
    this is the output
    @
    Starting /home/zafar/c++/dbExample-build-desktop/dbExample...
    "Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) QMYSQL: Unable to connect"
    false
    QSqlQuery::exec: database not open
    /home/zafar/c++/dbExample-build-desktop/dbExample exited with code 0
    @

    the commands in mysql displayed are here
    repectively to your commands

    @
    mysql> show databases;
    +--------------------+
    | Database |
    +--------------------+
    | information_schema |
    | cdcol |
    | mysql |
    | phpmyadmin |
    | test |
    | testTwo |
    +--------------------+
    6 rows in set (0.01 sec)

    mysql> use testTwo
    Database changed
    mysql> show tables
    -> ;
    +-------------------+
    | Tables_in_testTwo |
    +-------------------+
    | testTable |
    +-------------------+
    1 row in set (0.01 sec)

    @

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    • D Offline
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      doforumda
      wrote on last edited by
      #80

      any clues?

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      • L Offline
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        lyuts
        wrote on last edited by
        #81

        Change the 19th line to

        @QSqlQuery query(db);@

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

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          doforumda
          wrote on last edited by
          #82

          same error again

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          • L Offline
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            lyuts
            wrote on last edited by
            #83

            Take a look into mysql logs to see what happens when you are trying to connect from your application.

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

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              doforumda
              wrote on last edited by
              #84

              how can i check that mysql logs and from where?

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                lyuts
                wrote on last edited by
                #85

                [quote author="doforumda" date="1286880547"]how can i check that mysql logs and from where? [/quote]

                Try to find them:
                @find /opt/lampp -name log -type d@

                When you find the log directory, find a log for mysql and use tail utility:

                @tail -f /path/to/mysql.log@

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

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                  doforumda
                  wrote on last edited by
                  #86

                  this command didnt return something
                  @
                  root@zafar-laptop:/# find /opt/lampp -name log -type d
                  root@zafar-laptop:/#
                  @

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                    doforumda
                    wrote on last edited by
                    #87

                    i have a folder inside lampp with the name logs. is it the one which your are talking about

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                      lyuts
                      wrote on last edited by
                      #88

                      Solution 1:
                      @find /opt/lampp -name '*.log'@
                      This might need sudo'ing.

                      Solution 2:
                      If 1st fails then you need to find the config files for mysql (it should be located in /opt/lampp directory) and try to find out what is the location of mysql's log files.

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

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                        doforumda
                        wrote on last edited by
                        #89

                        there are 6 files in there but no mysql.log

                        these are the files
                        access_log, cgisock.1693, error_log, httpd.pid, php_error_log, ssl_request_log

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                          Dii
                          wrote on last edited by
                          #90

                          Don't bother with the log files, I guess Qt looks at the wrong place for the socket file...

                          Let's check this line in your mysql config file (my.cnf):

                          socket = /var/run/mysqld/mysqld.sock

                          You should find my.cnf in /etc/ or /etc/mysql/ ... I don't know ubuntu that much.

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                            doforumda
                            wrote on last edited by
                            #91

                            1st solution returns this
                            @
                            root@zafar-laptop:/# find /opt/lampp -name *.log
                            /opt/lampp/htdocs/xampp/contrib/sqlnet.log
                            @

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                              doforumda
                              wrote on last edited by
                              #92

                              with which editor i can view that .conf file. with gedit or something.

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                                lyuts
                                wrote on last edited by
                                #93

                                [quote author="¤ Dii ¤" date="1286881470"]
                                You should find my.cnf in /etc/ or /etc/mysql/ ... I don't know ubuntu that much.[/quote]

                                I don't think that this config will be in /etc. He uses lampp - a preconfigured bundle. That config might be in /opt/lampp.

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

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                                  Dii
                                  wrote on last edited by
                                  #94

                                  BTW a quick sum:

                                  • mysql is installed
                                  • database and tables are created
                                  • access is granted
                                  • qt code looks fine

                                  I see two possibilities here: libmysqlclient is missing, or the socket file is at different place.

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                                    doforumda
                                    wrote on last edited by
                                    #95

                                    the file my.cnf is in etc/mysql folder

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                                      Dii
                                      wrote on last edited by
                                      #96

                                      doforumda: use gedit

                                      sudo gedit /etc/mysql/my.cnf

                                      at least most of the ubuntu machines have the config file there.

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                                        doforumda
                                        wrote on last edited by
                                        #97

                                        this is the socket line in my.cnf

                                        @
                                        socket = /var/run/mysqld/mysqld.sock
                                        @

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                                          Dii
                                          wrote on last edited by
                                          #98

                                          ok then the wrong socket guess was wrong... but let's make it sure:

                                          sudo ls -l /var/run/mysqld/*

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