[TinyOWS-users] fids in database views

[Olivier Courtin]

On Sep 23, 2010, at 8:25 PM, Rahkonen Jukka wrote:

Jukka,

>> - User could overhead the fid by something else than PK (column must
>> be UNIQUE) in config.xml
>
> Sounds good to me.  However, it may be too hard to say "must" in the  
> last case. With views it may be impossible to guarantee that a  
> column is unique.  It can be checked for sure only after running the  
> whole query, which can be very expensive. In Geoserver case the  
> responsibolity is left for the one who configures server. If the  
> defined PK is not really unique, the service generates dublicate  
> fids which can for sure make troubles for WFS clients. I believe it  
> is easy to generate dublicate fids with Mapserver, too. However,  
> dublicate fids are usually not as bad thing for the end user than  
> getting no data at all may be. For example ogr2ogr converts such gml  
> files to totally valid shapefiles if I remember right.
>
> So would it be OK to accept that TinyOWS may generate in some  
> circumstances dublicate fids? If not, should there still be a  
> selection for "Strict" or "Liberal" modes?

It's a good point indeed,

I feel Ok with using a column regardless is Unique or not as it's a  
specific option choosen by the user.
It just have to be well documented, of course...

--
Olivier