On Wed, Jan 7, 2015 at 8:52 PM, <zuelpicher-wall-40@anonymised.com> wrote:
<<re-post of question in text format>>
Hi Geoserver-users and developers,
i have a question:
I have to create a WFS-T service backed by PostGIS using GeoServer. The
WFS-T is supposed to insert, update a delete features of one certain type.
Problem: A feature is made up of one main table "event". The "event" table
contains the only geometry. The event has a many-to-many relationship to a
"category" table. I.e. the result of one WFS-T transaction has to be an
INSERT on the "event" table plus several INSERTs on the "event_category"
table. "event_category" is just a N:M table consisting of the primary key
of "event" and "category". The primary keys on the tables are autogenerated
by PostGIS.
AFAIK there is no simple solution for such a constellation.
1) Which options do I have? Use app schema? Are there any extension points
I can use to alter the interaction with the database? I am a Java Developer.
2) What do you recommend?
You are right that in order to change multiple tables, you should be
working against complex features.
The app-schema data store is the only source of complex features GeoServer
has, its architecture is complex,
does not support editing, and has never been really though out to allow
editing.
In fact, while setting up the mappings from N simple feature sources to the
complex feature tree, you can
make a number of transformations that are not invertible, thus rendering
the overall complex feature
not really editable (or at least, partially not editable).
Anyways, have a look at the app-schema documentation here:
http://docs.geoserver.org/stable/en/user/data/app-schema/
and the store code here:
https://github.com/geotools/geotools/tree/master/modules/extension/app-schema
it should give you a feel of what you're up against
Other softwares are working with a simplified way of doing things, they
basically store
in the database into a field the GML of the full feature, in its complex
state, and
map out some of the fields as flat columns in the same table to allow for
fast flitering
and map rendering.
This would probably be an easier approach to the problem.
And oh, you will also have to upgrade the GeoTools GML encoder to parse
complex
features, right now there is only support for encode them.
All in all it's a significant chunk of work, no matter how you try to
address it.
Cheers
Andrea
--
GeoServer Professional Services from the experts! Visit
http://goo.gl/NWWaa2 for more information.
Ing. Andrea Aime
@geowolf
Technical Lead
GeoSolutions S.A.S.
Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy
phone: +39 0584 962313
fax: +39 0584 1660272
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