Re: [Geoserver-devel] question about schema.xml file... apologize

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

> > hi all,
> >
> > i'd like to ask you a question concerning schema.xml file and the 
> > DescribeFeatureType request...
> >
> > i tried to modify, via the web interface, one of my data's schema....
> >
> > so i modify the "Schema Base" and then for all "myFeature"'s attibutes 
> > i set "nilable" to false.
> >
> > then, when i performed a "DescribeFeatureType" request, the response 
> > schema shows all the attributes with "nillable" set to true....
> > wihle the schema.xml file generated is correct (located at 
> > /geoserver/data/featureTypes/myFeature/scema.xml)...
> >
> > so my question is : is the schema.xml file used by geoserver when 
> > answering a "DescribeFeatureType" request ? or esle how does the 
> > schema is produced ?
> >
> > thanks in advance.
> >
> > antoine.
> 
> 
> 
> hi all,
> 
> i apologize for the last mail... answers about how schema.xml file is 
> used are in the geoserver documentation...
> 
> but, there is still a thing i do not understand : it seems that the 
> schema.xml file generated after modification in the web interface is 
> ignore by geoserver when answering a "DescribeFeatureType" request 
> (attributes with "nillable" set to true in the answer while set to false 
> in the file). even if i create and then deploy a "geoserver.war" file 
> with the "schema.xml" file in the 
> "data/featureTypes/mydatastore_myfeature" directory the schema shown 
> does not correspond.... more over, "myfeature" is a table in a postgis 
> database and all attributes do have the "NOT NULL" constraint !
> 
> so i wonder how the schema is produced....
> 
> once again i apologize for wirting a mail before reading the documentation.
No need to apologize, this is a confusing area of geoserver, and indeed I 
am not exactly sure how it works, even though I wrote decent parts of the 
code.  THe thing I am no longer sure about is if/when we actually return 
the schema.xml file completely, and when GeoSErver users it to inform its 
generation.  The way we meant to code it, as far as I remember, was to 
return the schema.xml file directly if it was present, and to generate it 
if it was not.  But this may have been a bit subverted, since we end up 
using schema.xml information to control other parts of the application.  
In your case what we really should be doing is generating nillable 
information from GeoTools, generating the not null stuff on the fly.  But 
since we are not there yet, then your schema.xml file should be used, and 
if it is not, if geoserver is doing generation from postgis (and 
imperfect generation at that) then thats a bug.  I will try to look into 
it soon (and submit it to the task tracker if youc ould, so I dont forget 
about it).  

In addition, nillable is a particularly tricky case, where the ogc specs 
dont quite match up with XML intentions precisely.  Basically in xml I am 
pretty sure that if you allow nills then you are supposed to return an XML 
nil type.  But for the CITE tests of the OGC they dont check for 
nilleable, they check to make sure that its not included in the response.  
Granted for your case this doesnt matter, as you do not want to allow 
nills.  But yes, basically we do have more work to do on getting the 
DescribeFeatureTypes to have more control and exactly reflect the backend, 
though user customization of the schema.xml file _should_ work, and I will 
look into it for the next release. And could you try one thing for me?  
Try not working through the web administration interface at all, and see 
if you can hand edit the schema.xml file and have that one return.  
Because if that works then it can help me narrow down the problem, to the 
web admin interface clobbering stuff.

best regards,

Chris


> 
> thanks in advance.
> 
> antoine.
> 
> 
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