[Qt-interest] QSqlite Table not showing all rows in app

[William Lugg]

Bear with me, I'm new to this...

So If I understand you correctly, I should use your suggestion to get to total 
record count.  Then in my next record slot I should use the fetchMore method 
when I get to the last record in the current batch (assuming canFetchMore is 
true), right?
  
Now, for the last record slot, on the surface it seems like I would retrieve 
all the records, but as you said, I'd take a memory hit for it.  What would be 
a better approach while sticking within the MVC design paradigm?

Thanks for the help.
----
Bill Lugg
  Milstar Software Support
  Peterson AFB, CO
  No Micro$oft products were used to create this email.  
  God rules and if He needed a computer it would run Linux!

On Monday 08 February 2010 09:40:58 pm Scott Aron Bloom wrote:
> I suggest you DONT call the fetchMore...  Its a major memory hog to do
> so...
>
> Unless you need all the columns of all the rows, there is no reason
> to...  Dont forget the QSqlTableMode is acting as an interface between
> your views and the QSqlQuery...  So when you do a fetchMore, you are
> loading into memory, the complete database results.
>
> Working just on the QSqlQuery, will have a LOT less overhead for non
> View related items, without any memory overhead.
>
> Scott
>
> On Feb 8, 2010, at 5:39 PM, William Lugg wrote:
> > That was the ticket. I had looked at the help for QSqlTableModel and
> > completely overlooked the fetchMore and canFetchMore methods. for my
> > situation, I believe a while loop in the constructor to retrieve the
> > rest of the records will solve the problem. I suspected it was
> > something like this but couldn't find the key to unlock the problem.
> >
> > Thanks for the help.
> > ----
> > Bill Lugg
> > Milstar Software Support
> > Peterson AFB, CO
> > No Micro$oft products were used to create this email.
> > God rules and if He needed a computer it would run Linux!
> >
> > On Monday 08 February 2010 05:10:29 pm Scott Aron Bloom wrote:
> > > I haev found that the rowCount() does NOT contain all the rows as
> >
> > long
> >
> > > as the canFetchMore returns true. The model only loads 250 rows or
> >
> > so
> >
> > > into memory at a time.
> > >
> > > One way to find all the rows...
> > >
> > > QSqlQuery query = model->query();
> > >
> > > query.last();
> > > int numRows = query.at();
> > >
> > > Scott
> > >
> > > On Feb 8, 2010, at 3:54 PM, William Lugg wrote:
> > > > I'm sure this would work, but it seems to defeat the whole MVC
> > > > design pattern offered by Qt. It also doesn't solve the problem of
> > > > the QDataWidgetMapper and/or the model running out of records
> > > > prematurely at 250 records.
> > > >
> > > > Any ideas as to why the QSqlTableModel is under reporting the size
> > > > of the table would be greatly appreciated.
> > > >
> > > > Thanks.
> >
> > _______________________________________________
> > Qt-interest mailing list
> > Qt-interest at trolltech.com
> > http://lists.trolltech.com/mailman/listinfo/qt-interest

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