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SQLite DB at Runtime

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  • SGaistS SGaist

    Hi,

    That is correct and you had it wrong in your original code.

    @silenzio76 said in SQLite DB at Runtime:

    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");

    Change ":memory:" to the path you want to use and it should work correctly now.

    One additional thing, you should use QStandardPaths to get a suitable folder to store your database. On most OS, installing an application is done in a read-only part of your system, so putting your database in the same folder as your application will fail.

    [edit: fixed unclear phrase about path SGaist]

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    Silenzio76
    wrote on last edited by
    #7

    @sgaist Obvously it works then how can i create the db file at runtime?

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    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #8

      Meaning allow the user to select the folder where to store the database ?

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

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      • SGaistS SGaist

        Meaning allow the user to select the folder where to store the database ?

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        Silenzio76
        wrote on last edited by
        #9

        @sgaist that will be in a second phase, for now I need create the db file( db.sqlite ?)at runtime

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #10

          If the file doesn't exist, it will be created. That's how SQLite works (it's nothing related to the plugin).

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

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          • SGaistS SGaist

            If the file doesn't exist, it will be created. That's how SQLite works (it's nothing related to the plugin).

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            Silenzio76
            wrote on last edited by
            #11

            @sgaist ok, if will be created my question is where is put the file qith the ":memory: condition after the app is terminated?
            Because the next time I will need to connect to it and retrieve the saved datas.

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

              There's no file created when using the special keyword ":memory:".

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

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              • SGaistS SGaist

                There's no file created when using the special keyword ":memory:".

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                Silenzio76
                wrote on last edited by
                #13

                @sgaist the problem is that, I need to create the file at the first start of the app.

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

                  @silenzio76 said in SQLite DB at Runtime:

                  the problem is that, I need to create the file at the first start of the app.

                  So where is your problem - simply pass the filename to setDatabaseName() instead ":memory:"...

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                  • Christian EhrlicherC Christian Ehrlicher

                    @silenzio76 said in SQLite DB at Runtime:

                    the problem is that, I need to create the file at the first start of the app.

                    So where is your problem - simply pass the filename to setDatabaseName() instead ":memory:"...

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                    Silenzio76
                    wrote on last edited by
                    #15

                    @christian-ehrlicher done but don't work, it's in the first post:

                    db.setDatabaseName(dbPath);
                    
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                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #16

                      In your first post, your db object is invalid. addDatabase is a static method that returns a QSqlDatabase object that is the one that you should use to setup the database connection. Hence my comment on your new version using :memory:., you are using QSqlDatabase correctly on that one. So as already said, you can now use a path to a database file. If it's still not working, then check the errors and also check that you have the write permission on the folder you want to store your database in.

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

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                      • O Offline
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                        Oshio
                        wrote on last edited by Oshio
                        #17

                        @Silenzio76
                        I don't have the time to read your code, but take a look at my SQLiteSave library: https://github.com/Oshio09/Oshio_Qt_Static_Libs

                        Its not documented but you will find the interface very intuitive. Try to maintain a copy of the repository, because I just created after I saw your question. I may delete or rename it in the future.

                        There is a QT Test project that I wrote, read and use as an example on how to use the library.
                        I don't know how much you understand about Qt so I wrote some simple steps on how to run the tests at the README file.

                        I wrote this lib last week so I didn't had time to do an extensive test, try to run and let me know of any errors. As @SGaist pointed out QStandardPaths is good practice, SQLiteSave makes use of it.

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                        • O Oshio

                          @Silenzio76
                          I don't have the time to read your code, but take a look at my SQLiteSave library: https://github.com/Oshio09/Oshio_Qt_Static_Libs

                          Its not documented but you will find the interface very intuitive. Try to maintain a copy of the repository, because I just created after I saw your question. I may delete or rename it in the future.

                          There is a QT Test project that I wrote, read and use as an example on how to use the library.
                          I don't know how much you understand about Qt so I wrote some simple steps on how to run the tests at the README file.

                          I wrote this lib last week so I didn't had time to do an extensive test, try to run and let me know of any errors. As @SGaist pointed out QStandardPaths is good practice, SQLiteSave makes use of it.

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                          Silenzio76
                          wrote on last edited by
                          #18

                          @oshio Thank You, you'ra are very usefull!!!

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