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QTableview data disappear..

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  • Christian EhrlicherC Christian Ehrlicher

    @TheCipo76 said in QTableview data disappear..:

    mDatabase.close();

    How should this work? A QSqlModel needs access to the database at any time...

    TheCipo76T Offline
    TheCipo76T Offline
    TheCipo76
    wrote on last edited by
    #7

    @Christian-Ehrlicher as you see lower..

    0_1545298637152_Schermata 2018-12-20 alle 10.35.51.png

    works!

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    • Christian EhrlicherC Offline
      Christian EhrlicherC Offline
      Christian Ehrlicher
      Lifetime Qt Champion
      wrote on last edited by
      #8

      It works as long as the model does not need to refetch data from the database (e.g. due to scrolling or other circumstances).

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      TheCipo76T 1 Reply Last reply
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      • Christian EhrlicherC Christian Ehrlicher

        It works as long as the model does not need to refetch data from the database (e.g. due to scrolling or other circumstances).

        TheCipo76T Offline
        TheCipo76T Offline
        TheCipo76
        wrote on last edited by TheCipo76
        #9

        @Christian-Ehrlicher No, i'have tried to scroll and works fine.

        This is only view of DB data.. no need to modify nothing in this dialog
        and no need to reload data

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        • Christian EhrlicherC Offline
          Christian EhrlicherC Offline
          Christian Ehrlicher
          Lifetime Qt Champion
          wrote on last edited by
          #10

          I'm giving up... would you please at least try to not to close the database and see if your problem goes away?

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          Visit the Qt Academy at https://academy.qt.io/catalog

          TheCipo76T 1 Reply Last reply
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          • Christian EhrlicherC Christian Ehrlicher

            I'm giving up... would you please at least try to not to close the database and see if your problem goes away?

            TheCipo76T Offline
            TheCipo76T Offline
            TheCipo76
            wrote on last edited by TheCipo76
            #11

            @Christian-Ehrlicher Yes, i have putted "//" before close database instruction

            //mDatabase.close();
            

            but warning still remain..

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            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #12

              Are you calling QSqlDatabase::addDatabase("QMYSQL"); in several places in your application ?

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              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

              TheCipo76T 1 Reply Last reply
              1
              • SGaistS SGaist

                Are you calling QSqlDatabase::addDatabase("QMYSQL"); in several places in your application ?

                TheCipo76T Offline
                TheCipo76T Offline
                TheCipo76
                wrote on last edited by TheCipo76
                #13

                @SGaist Yes, in every dialog who need to connect to database..

                but in every dialog call

                ordforauto::~ordforauto()
                {
                    if (aDatabase.open()) {
                        aDatabase.close();
                    }
                QSqlDatabase::removeDatabase("QMYSQL");
                    delete ui;
                }
                

                in the code or at least in the unload istructions as you see

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                • Christian EhrlicherC Offline
                  Christian EhrlicherC Offline
                  Christian Ehrlicher
                  Lifetime Qt Champion
                  wrote on last edited by
                  #14

                  http://doc.qt.io/qt-5/qsqlquery.html#details

                  Warning: You must load the SQL driver and open the connection before a QSqlQuery is created. Also, the connection must remain open while the query exists; otherwise, the behavior of QSqlQuery is undefined.

                  Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
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                  TheCipo76T 1 Reply Last reply
                  1
                  • SGaistS Offline
                    SGaistS Offline
                    SGaist
                    Lifetime Qt Champion
                    wrote on last edited by
                    #15

                    Why are you doing it like that ? There's no need to nuke and recreate the connection each time.

                    If you really want to do it like that, then you should create a connection with a different name in each of your dialog.

                    Because currently, you are manipulating the default connection from several places in a wrong manner.

                    Interested in AI ? www.idiap.ch
                    Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                    TheCipo76T 1 Reply Last reply
                    2
                    • SGaistS SGaist

                      Why are you doing it like that ? There's no need to nuke and recreate the connection each time.

                      If you really want to do it like that, then you should create a connection with a different name in each of your dialog.

                      Because currently, you are manipulating the default connection from several places in a wrong manner.

                      TheCipo76T Offline
                      TheCipo76T Offline
                      TheCipo76
                      wrote on last edited by
                      #16

                      @SGaist ok, i create the connection in the main window
                      and then only open/close database tables in every dialog?

                      is it right?

                      1 Reply Last reply
                      0
                      • Christian EhrlicherC Christian Ehrlicher

                        http://doc.qt.io/qt-5/qsqlquery.html#details

                        Warning: You must load the SQL driver and open the connection before a QSqlQuery is created. Also, the connection must remain open while the query exists; otherwise, the behavior of QSqlQuery is undefined.

                        TheCipo76T Offline
                        TheCipo76T Offline
                        TheCipo76
                        wrote on last edited by TheCipo76
                        #17

                        @Christian-Ehrlicher i will check all dialogs.. but i think that is what i've done..

                        jsulmJ 1 Reply Last reply
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                        • TheCipo76T TheCipo76

                          @Christian-Ehrlicher i will check all dialogs.. but i think that is what i've done..

                          jsulmJ Offline
                          jsulmJ Offline
                          jsulm
                          Lifetime Qt Champion
                          wrote on last edited by
                          #18

                          @TheCipo76 As shown here: http://doc.qt.io/qt-5/qsqldatabase.html
                          Create and open db connection:

                          QSqlDatabase db = QSqlDatabase::addDatabase("QPSQL");
                          db.setHostName("acidalia");
                          db.setDatabaseName("customdb");
                          db.setUserName("mojito");
                          db.setPassword("J0a1m8");
                          bool ok = db.open();
                          

                          When you need the connection just get it:

                          QSqlDatabase db = QSqlDatabase::database();
                          

                          No need to open and close it all the time.

                          https://forum.qt.io/topic/113070/qt-code-of-conduct

                          TheCipo76T 1 Reply Last reply
                          4
                          • jsulmJ jsulm

                            @TheCipo76 As shown here: http://doc.qt.io/qt-5/qsqldatabase.html
                            Create and open db connection:

                            QSqlDatabase db = QSqlDatabase::addDatabase("QPSQL");
                            db.setHostName("acidalia");
                            db.setDatabaseName("customdb");
                            db.setUserName("mojito");
                            db.setPassword("J0a1m8");
                            bool ok = db.open();
                            

                            When you need the connection just get it:

                            QSqlDatabase db = QSqlDatabase::database();
                            

                            No need to open and close it all the time.

                            TheCipo76T Offline
                            TheCipo76T Offline
                            TheCipo76
                            wrote on last edited by
                            #19

                            @jsulm Ok, i've modify all my project and all works ok!

                            Thanks to all for help!

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