Stephane Fellah wrote: > Jody, > My comment are inline > Thanks muchly :-) > [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. > Understood, your best bet is to go to the complex-features branch if you need something today, or if you need something in the near future help out on the feature model branch. >> 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. > Interesting, I am new to WFS 1.1 thank you for the example :-) Question is a "joined" feature the expected result of that request? And if so is the feature flattened? Or would it have two attributes "A" and "B"? This is very cool as it is close to an earlier proposal for doing joins in geotools... > 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. > Interesting, let me think about it some - are you up for the geotools IRC meeting in a couple of hours time? If not we could have a breakout IRC on the topic. Exciting. > I think the only changes required are in query builder for each plug-ins. Do > I miss something here ? > Not too much, but I am a bit hesitent to proceed without a good talk to Justin who is working on the feature model branch.
For reference: - The complex-feature branch makes use of direct SQL to make queries involving joins. - My idea for doing joins after the FM branch was to use a FeatureCollection method to set up the model (aka a A/subject equals B/subject in your example) and then use featureCollection.subCollection( filter ) for the bbox half of your query. Jody _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
