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    Selecting data from mysql using qt?

    General and Desktop
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    • D
      doforumda last edited by

      sorry i couldnt notice Dii user

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      • L
        lyuts last edited by

        Wow, mysql is full of surprises. Never got those with psql. ¤ Dii ¤, does it have \q command?

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

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        • D
          doforumda last edited by

          yes i get into mysql command line

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          • D
            doforumda last edited by

            whats the reason that my database is not opening in qt?

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            • D
              Dii last edited by

              lyuts: yes \q is working too

              doforumda: ok, so get into the mysql comand line with the command above

              /opt/lampp/bin/mysql -D testTwo -h localhost -u root -p

              and then do this:

              grant all on testTwo.* to 'root'@'localhost' ;

              Then we have a working mysql, and the rights are granted, we can get back to your Qt program.

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              • L
                lyuts last edited by

                I hope the next post will be like "Hooray, I got it working!!!" :)

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

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                • D
                  doforumda last edited by

                  there is an error in sql syntax
                  @
                  mysql> grant all on testTwo.* to ‘root’@’localhost’;
                  ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '��root’@’localhost’' at line 1
                  @

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                  • D
                    Dii last edited by

                    Ok, back to your Qt program:

                    @#include <QApplication>
                    #include <QtSql>

                    int main(int argc, char *argv[])
                    {
                    QCoreApplication a(argc, argv);

                    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
                    db.setDatabaseName("testTwo");
                    db.setUserName("root");
                    db.setPassword("");
                    db.setHostName("localhost");
                    
                    bool ok = db.open();
                    qDebug() << ok;
                    
                    QSqlQuery query;
                    query.exec&#40;"SELECT firstname,lastname FROM testTable"&#41;;
                    while(query.next()) {
                        QString firstName = query.value(0).toString();
                        QString secondName = query.value(1).toString();
                        qDebug() << "First Name: " << firstName << "Last Name:" << secondName;
                        qDebug() << db.lastError();
                    }
                    return 0;
                    

                    }@

                    Notice, we don't set a password here.
                    The end is 'return 0' instead of 'a.exec()', and it won't hang. The exec() starts the main event loop, and you don't use it here...

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                    • L
                      lyuts last edited by

                      I think you need to check apostrophes in that command.

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

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                      • D
                        Dii last edited by

                        ok, you have wrong apostrof type there. I mean this >> '

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                        • D
                          doforumda last edited by

                          i tried without apostrophes as well but same error

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                          • D
                            Dii last edited by

                            nope, you had ` before the root and not '
                            that was the error

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                            • D
                              Dii last edited by

                              ok, wait a second, I checked it in the meantime and it won't work without password, stay tuned, I post the right command

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                              • D
                                doforumda last edited by

                                you mean like this
                                grant all on testTwo.* to root@localhost ;
                                if yes it also displaying same error

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                                • D
                                  Dii last edited by

                                  so, here we go:

                                  grant all on testTwo.* to 'root'@'localhost' identified by 'password';

                                  Make the right apostrophes! :) You have to set the password in your Qt app too.

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                                  • D
                                    Dii last edited by

                                    ok, wait I see

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                                    • D
                                      Dii last edited by

                                      the Devnet's forum motor changes the apostrophes somehow... use the straight apostrophes everywhere
                                      I mean this @'@

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                                      • D
                                        doforumda last edited by

                                        mysql query did its job its now successful but when i use qt code and try to make it run it displays same error

                                        @
                                        Starting /home/zafar/c++/dbExample-build-desktop/dbExample...
                                        false
                                        QSqlQuery::exec: database not open
                                        /home/zafar/c++/dbExample-build-desktop/dbExample exited with code 0
                                        @

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                                        • D
                                          doforumda last edited by

                                          wait i think the query is not sucessful because it displays this message 0 rows affected
                                          @
                                          mysql> grant all on testTwo.* to 'root'at'localhost' identified by 'password';
                                          Query OK, 0 rows affected (0.01 sec)
                                          @

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                                          • L
                                            lyuts last edited by

                                            Add this to your code after connecting:

                                            @qDebug() << db.lastError().text();@

                                            And tell us what the error is.

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

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