Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. QTableview data disappear..
Forum Updated to NodeBB v4.3 + New Features

QTableview data disappear..

Scheduled Pinned Locked Moved Solved General and Desktop
19 Posts 4 Posters 2.3k Views 1 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • Christian EhrlicherC Offline
    Christian EhrlicherC Offline
    Christian Ehrlicher
    Lifetime Qt Champion
    wrote on last edited by
    #6

    @TheCipo76 said in QTableview data disappear..:

    mDatabase.close();

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

    Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
    Visit the Qt Academy at https://academy.qt.io/catalog

    TheCipo76T 1 Reply Last reply
    1
    • 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!

      1 Reply Last reply
      0
      • 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).

        Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
        Visit the Qt Academy at https://academy.qt.io/catalog

        TheCipo76T 1 Reply Last reply
        0
        • 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

          1 Reply Last reply
          0
          • 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?

            Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
            Visit the Qt Academy at https://academy.qt.io/catalog

            TheCipo76T 1 Reply Last reply
            0
            • 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..

              1 Reply Last reply
              0
              • 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 ?

                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
                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

                  1 Reply Last reply
                  0
                  • 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/
                    Visit the Qt Academy at https://academy.qt.io/catalog

                    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
                          0
                          • 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!

                              1 Reply Last reply
                              0

                              • Login

                              • Login or register to search.
                              • First post
                                Last post
                              0
                              • Categories
                              • Recent
                              • Tags
                              • Popular
                              • Users
                              • Groups
                              • Search
                              • Get Qt Extensions
                              • Unsolved