Re: [gnome-db] Tree-structured data

[Rodrigo Moya <rodrigo gnome-db org>]

On Mon, 2006-01-30 at 12:45 +0100, Diego Zuccato wrote:
> Vivien Malerba wrote:
> 
> >>I'd propose to consider aupport for a tree model, not only for list
> >>model. I've already considered the problems, and it seems they can be
> [...]
> > The GdaDataModel has a list concept and not a tree concept because
> > this is the concept behind relational databases (they don't do trees).
> I know. But aren't we going to use a higher level when using widgets?
> When "presenting" data to the user, readability is all. A tabular format
> can be what's in the db, not what the user wants to see (at least not
> always).
> 
> > For the performances problem, the last version of libgda includes two features:
> > * a GdaDataProxy dete model which allows to define arbitrary size
> > "chuncks" of data (by default 300 lines): you give it a GdaDataModel,
> > and the GdaDataProxy will only contain 300 lines of that model (of
> > course you can then change which 300 lines are displayed). This object
> > is used in the form and grid widgets of libgnomedb.
> But I have to actually FILL the GdaDataModel from the DB (that can be
> quite slow... maybe over a modem connection).
> At least there should be a widget that supports it in gnomedb... Or
> should every programmer implement his own GdaDataModel->GtkTreeModel
> converter?
> 
ideally, we should be using GtkTreeModel directly, but this is in GTK,
so libgda can't depend on it. I've talked a few times with the GTK
maintainers about having the tree model in Glib, but that is a difficult
task given the dependencies.
-- 
Rodrigo Moya <rodrigo gnome-db org>