Re: [gnome-db] introspection issue

On 8 April 2011 22:12, Murray Cumming <[email protected]> wrote:
> GObject+Introspection is working quite well for me now with libgda.
> Thanks. I am glad that pygda is now obsolete, so it's one less module
> for me to maintain.
>
> However, I'm getting an error when trying to get the values from the
> DataModel with get_value_at(). For instance, this script
> http://git.gnome.org/browse/pygda/tree/examples/gda/select.py?h=introspection
> produces this error:
>
> Traceback (most recent call last):
>  File "./select.py", line 61, in <module>
>    main ()
>  File "./select.py", line 57, in main
>    print "        value=", data_model.get_value_at(col_index,
> row_index);
>  File "/opt/gnome230/lib/python2.7/site-packages/gi/types.py", line 44,
> in function
>    return info.invoke(*args)
> TypeError: unknown type (null)
>
>
> Presumably it doesn't like GdaValues with GType=0 (when
> gda_value_is_null(gvalue) is true).

Yes, the a GValue with a 0 GType represents a SQL NULL value, whereas
if the returned value is NULL (the C NULL) then it means there was an
error retreiving the value, hence the difference between the 2.

Regards,

Vivien