Jody, My comment are inline
> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:geotools-devel- > [EMAIL PROTECTED] On Behalf Of Jody Garnett > Sent: Monday, June 12, 2006 8:11 AM > To: Stephane Fellah > Cc: 'Geotools-devel' > Subject: Re: [Geotools-devel] Support of Alias in Query. > > Stephane Fellah wrote: > > > > Hi, > > > > > > > > The WFS specification clearly specifies that aliases can be used in > > the typeName attribute of the GetFeature request. However the OGC > > Filter specification remains completely silent about how the usage of > > aliases in the OGC Filter. So I went back to Peter Vretanos to ask > > clarifications about this. Here an extract from what he sent to me > > that I want to share with you in order to enhance to alias support > > (useful for joins in query) in the Geotools. > > > Thanks for the background, would love to know: > a) which version of WFS you are thinking of? Currently we only have a > WFS 1.0 implementation based on geotools > b) if WFS has made any progress on defining joins in a query? > [Stephane] My change request is mainly related to the Query and OGC Filter API in Geotools, not WFS specifically (which would be WFS 1.1 for join support). In fact I am mainly interested to do join on database directly. > My working understanding is this: > - joins may be considered in light of the CAT 2 practice of having more > then one filter per query > - WFS 1.0 and WFS 1.1 do not support joins > - geotools 2.2.x does not have an implementation of XPath that supports > anything beyond "name" > [Stephane] Correction: WFS 1.1 supports joins as shown in my example in my former mail. There is no change required in the OGC Filter to supports joins because PropertyIsEquals can be used to perform the joins on properties. The only difference if the internal processing of aliases in the property name xpath. The external API of the Filter remains the same. I think the only changes required are in query builder for each plug-ins. Do I miss something here ? > For a JXPath based geotools implementation look into the Feature Model > branch, or complex-feature branch. Currently we lack anyone with > time/budget to bring this work home promptly - but are pressing ahead > slowly regardless. I do have a design capable of doing joins that is one > of my writing projects, but I am not really interested until the feature > model comes home. > > To answer your questions: > > > > Does Geotools supports aliases in the typename ? > > > no > > > > Does the different plugins such as Oracle Spatial, MYSQL,ArcSDE > > leverage these capabilities ? > no > > Right now the geotools community is focused on bringing some of the RnD > branches home, namely a Grid Covearge branch and the above mentioned > feature model branch. We may be able to look into what support JXPath > has for alias, probably something that happens out of the box. > > Jody > > > > _______________________________________________ > Geotools-devel mailing list > Geotools-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/geotools-devel [Stephane] Best regards Stephane _______________________________________________ Geotools-devel mailing list Geotools-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-devel
