Re: [Geoserver-users] feature ids

[Chris H. <ch...@op...>]

Yeah, it's a tough trade-off, since if you let users specify any 
attribute they want they may not pick one that is actually unique.  The 
spec insists that featureids are actually unique.  From what I can tell 
mapserver doesn't support the featureid filter, which means it doesn't 
so much matter what they let people put there.

So we try to only use unique columns and values, that the data type 
guarantees will be unique.  I'd like to allow a bit more configuration 
options, but it's quite a bit of work, and I think we cover the majority 
of use cases.

Chris

Justin Deoliveira wrote:
> Hi Eric,
> 
> How feature id's are generated are actually dependent on the underlying
> datasource. For instance, in a shapefile the feature id is generated by
> the "row number", in a relational database the primary key is used ( if
> one exists). If all else fails GeoServer will generate its own on the fly.
> 
> Unfortunately what attribute is the feature id is not as configurable as
> it is in mapserver, ie you can just mark an attribute as the id. You
> said you were using postgis yesterday, correct? What I suggest is that
> you try making your name column the primary key of your postgis table.
> 
> -Justin
> 
> Eric Lemoine wrote:
>> Hi list
>>
>> As far as I understand, when responding to a WFS GetFeature request,
>> geoserver generates featureids using the following scheme: feature #1
>> gets "<layer>.1", feature #2 gets "<layer>.2", etc.
>>
>> What I'd like is control the way featureids are generated. More
>> particularly, I'd like geoserver to derive featureids from a certain
>> layer attribute (e.g. the feature name).
>>
>> With mapserver you can do exactly that by expliciting the featureid to
>> attribute association. Using this in your mapfile:
>>
>> LAYER
>>   NAME foo
>>   METADATA
>>     "wfs_title" "foo"
>>     "gml_featureid" "ID" ## <-- FID TO ATTR ASSOCIATION
>>     "gml_include_items" "all"
>>   END
>>   ...
>>
>>
>> Can I configure geoserver to specify such as association?
>>
>> Thanks a lot,
>>
> 
> 

-- 
Chris Holmes
The Open Planning Project
http://topp.openplans.org