Re: [gnome-db] How do I read a GdaNumeric as a gdouble?

[Murray Cumming <murrayc murrayc com>]

On Wed, 2006-03-15 at 14:00 -0600, Daniel Espinosa wrote:
> 
> 
> 2006/3/15, Murray Cumming <murrayc murrayc com>:
>         On Wed, 2006-03-15 at 13:33 +0100, Vivien Malerba wrote:
>         > On 3/15/06, Juan Pablo <jpdborgna yahoo com ar> wrote:
>         > > With v=(GdaValue *)
>         > >
>         gda_data_model_get_value_at(dm,gda_data_model_get_column_position(dm,"stock1a"),0); 
>         > > i get a numeric (from database) and i want to use it like
>         this (in the
>         > > ideal world...)
>         > >
>         gtk_spin_button_set_value(GTK_SPIN_BUTTON(lookup_widget(widget,"stock1a")),
>         > > gda_value_get_double(v)); 
>         > > But it is numeric, so im afraid i have to stringify it and
>         then
>         > > g_strotod it (it works but its ugly).
>         > >
>         > > �Is there any direct way to do it?
>         >
>         > For the moment you need to either use a string
>         representation, or 
>         > build your own gdouble value from the GdaNumeric structure.
>         >
>         > However, I've added in my local working repository a
>         function to
>         > transform a GdaValue into another one called
>         g_value_transform() which 
>         > you'll be able to use instead (but I've not yet committed
>         it).
>         
>         Some kind of get_value_numeric_as_double() would be a lot
>         simpler.
>         
>         GdaNumeric contains a string representation of the number
>         (presumably as 
>         per the C locale, hopefully). At the moment, I need to parse
>         that string
>         representation to a double myself.
> 
> Why it is used the GdaNumeric structure?
> 
> Is realy necesary?
> 
> If we think about that GdaValue is a GValue, you can store a long
> value and get transform, etc.

I don't believe that a long can store a floating point value (with a
decimal point).

> What about the precision and width, values?

I ignore the other values. I don't how to use them.

(If you're interested, search for GdaNumeric in this:
http://cvs.gnome.org/viewcvs/glom/glom/data_structure/glomconversions.cc?view=markup
)

>  I can investigate if it is necesary or exist an equivalent in GLib.

> 
-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com