Hi all, Giovanni Manghi run to a problem with NULL values in a shapefiles (earlier post). I tested it but couldn't reproduce the error in 1.7.1. But I found out some other issues with NULL handling in shapefiles.
Shapefiles don't support null values at least not in ESRI-world. Though OGR should support reading and writing null values with shapefiles. Don't know how but it should. When I opened a shapefile created by arcgis geoprosessor, qgis somehow shows all the 0 and '' values as a NULL values. I'm now able to search a field with IS NULL syntax and qgis returns what is expected. I'm also able to modify the table and change some values to real zeros. Now a search finds only 0 values when searched [field] = 0. But when I save this layer with Save as... to a new shapefile all the NULL values in numeric fields are converted to 0 and in text field to ''. In the attribute table '' values in text fields still shows as NULL but when I try to search only [field] = '' works. All zeros in numeric fields shows as 0 and not NULL. Is there some logic or is this a bug to report? Thanks -Lauri Kajan _______________________________________________ Qgis-developer mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-developer
