[fdo-internals] FDO OGR Provider: NULL values in integer Field

[Greg Boone]

In the past, we have posted patches to posted releases. As an example, you can refer to the Patches section for FDO 3.3.1 at

http://fdo.osgeo.org/content/fdo-331-downloads

If you need any assistance, I would be happy to help with any build/post tasks.

Greg


-----Original Message-----
From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Traian Stanev
Sent: Monday, February 22, 2010 2:57 PM
To: fdo-internals at lists.osgeo.org
Subject: RE: [fdo-internals] FDO OGR Provider: NULL values in integer Field


If I get a chance in the next week, I might port the fix to 3.4 and post a new build of the provider.

Traian


-----Original Message-----
From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Traian Stanev
Sent: Monday, February 22, 2010 2:20 PM
To: fdo-internals at lists.osgeo.org
Subject: RE: [fdo-internals] FDO OGR Provider: NULL values in integer Field


Hi,

I fixed this bug on September 19, 2009. Here is my svn commit (revision 4928) log:

Correct implementation of FdoIFeatureReader::IsNull().
Previously, the function always returned false and then attempts to get a null value would return the default value.



Unfortunately, MapGuide uses ancient builds of FDO.


Traian


-----Original Message-----
From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Gabriele Monfardini
Sent: Monday, February 22, 2010 1:43 PM
To: fdo-internals at lists.osgeo.org
Subject: [fdo-internals] FDO OGR Provider: NULL values in integer Field

Hi all,

I'm using FDO 3.4.0 OGR provider to connect to a PostgreSQL db (using a modified GDAL library built with PostgreSQL support).
In fact, I'm using Mapguide Open Source 2.1 that uses FDO 3.4.0.

I'm trying to stylize a layer in Mapguide, aka doing a query that involves searching for NULL (and NOT NULL) values in an integer field of a PostgreSQL table.
After a lot of fiddling it seems that tuples with NULL values can be retrieved only searching for tuples that have the value 0 in that field.

This is obviously very odd since 0 is a valid integer, so it appears that I cannot distinguish tuples with proper zeros in the field from tuples with unknown values.
Moreover ogr itself is able to support NULL values correctly.

I've read this previous thread
http://n2.nabble.com/RE-mapguide-internals-Exception-thrown-on-null-values-tp2051195p2051195.html.

Is FDO OGR provider avoiding NULL value intricacy when dealing with integer fields converting the NULL value in a zero?

Do you suggest opening a bug against FDO OGR provider or it is a by-design behaviour of FDO OGR provider?

Regards,

Gabriele
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