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    Selecting data from mysql using qt?

    General and Desktop
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    • M
      MTK358 last edited by

      Why not just

      @#include <QtCore>
      #include <QtSql>@

      and not worry about every single class you use?

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      • T
        tony last edited by

        That can be a solution only when you're testing something. So, in this case, I agree with you, let's avoid such worries.

        But if your project grows up, it's better to include what's needed, otherwise your compilation time can increase a lot.

        T.

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        • D
          doforumda last edited by

          i add #include <QVariant>

          now it is saying
          @
          QSqlQuery::exec: database not open
          @

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          • D
            Dmytro last edited by

            Try to use QSqlQuery::lastError() for find problem

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            • D
              doforumda last edited by

              what is the problem now in my code why it is not opening database?

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              • T
                tony last edited by

                Did you leave

                @
                //bool ok = db.open();
                @

                commented?

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                • D
                  doforumda last edited by

                  well i changed my code to this and added lastError as well

                  @
                  #include <QApplication>
                  #include <QSqlDatabase>
                  #include <QSqlError>
                  #include <QSqlQuery>
                  #include <QDebug>
                  #include <QString>
                  #include <QVariant>
                  //#include <QtCore>
                  //#include <QtSql>
                  //#include "../connection.h"
                  #include "db.h"

                  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();
                  
                  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 a.exec&#40;&#41;;
                  

                  }
                  @

                  it still says QSqlQuery::exec: database not open

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                  • D
                    doforumda last edited by

                    it is still as commented
                    [quote author="Antonio Di Monaco" date="1286818410"]Did you leave

                    @
                    //bool ok = db.open();
                    @

                    commented?[/quote]

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                    • D
                      Dmytro last edited by

                      Try uncomment line 23

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                      • D
                        doforumda last edited by

                        i uncomment line 23 and comment everything below line 23 then it just says
                        @
                        Starting /home/zafar/c++/dbExample-build-desktop/dbExample...
                        @

                        and stucks there

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                        • D
                          Dmytro last edited by

                          OH! You use SQL code before
                          a.exec()
                          !
                          Are you sure?

                          Create standart QT GUI application and wrote sql code in mainwindow module.

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                          • D
                            doforumda last edited by

                            i am new to qt. how can i create Qt Gui App and do you mean i should write sql code in mainwindow.h file?

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                            • D
                              doforumda last edited by

                              right now i have three files. db.h, db,cpp and main.cpp

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                              • D
                                Dmytro last edited by

                                Run QT Creator.
                                Use menu File/new file or project.
                                Select QT Gui application.
                                ...
                                and select SQL checkbox
                                ...
                                and write sql code in MainWindow.cpp
                                ...
                                and see SQL Example please

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                                • D
                                  doforumda last edited by

                                  well i tried "File/new file or project and select qt gui app" but i ddint find any sql checkbox anywhere in creating new project

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                                  • D
                                    Dmytro last edited by

                                    no coments...
                                    How can I send you screenshot?

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                                    • D
                                      doforumda last edited by

                                      you can add pictures here as screenshots or if you want my email address i ll give you that as well for screenshots

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                                      • D
                                        doforumda last edited by

                                        anyone who can help?

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                                        • D
                                          Dmytro last edited by

                                          !http://hin.dp.ua/files/down/qt_scr.PNG(my screenshot)!

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                                          • D
                                            doforumda last edited by

                                            well i dont have that option. here is what i get
                                            when i click file/new file or project then this screenshot
                                            "Your text to link here...":http://www.freeimagehosting.net/uploads/702f633ae7.png
                                            then i keep clicking next getting the follwoing screenshots
                                            "Your text to link here...":http://www.freeimagehosting.net/uploads/ab872acfb8.png
                                            "Your text to link here...":http://www.freeimagehosting.net/uploads/45c51ab364.png
                                            "Your text to link here...":http://www.freeimagehosting.net/uploads/84605eae46.png
                                            "Your text to link here...":http://www.freeimagehosting.net/uploads/84605eae46.png

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