Thanks, Andrew, we would certainly be very interested in hearing about both your ideas and progress.
On 15/12/10 21:51, Andrew Chamberlain wrote: > Hi Ben, > > Many thanks for that. Sounds like there's quite a few obstacles at the > moment. I feel that whatever mapping solution is eventually used to > implement transactions, it should *ideally* be also used to deliver the > complex features in the read direction. Given the one-way nature of CQL, > this would probably mean looking for an alternative ORM to that currently > used. You mention this as a possibility, so I hope it's not too abhorrent to > suggest undoing (some of) your hard work! > > One of the options we're looking at is the use of RIF to define how the > complex features map back and forth from simple ones. There is much > discussion about whether RIF is mature enough, but it's certainly one of the > options we're looking at. Obviously, there's still quite a bit of background > reading and research we need to do, but the questions you raise all need > answering and will help us evaluate the different options. > > I'll certainly keep you and the group posted with progress. > > Regards, > > Andy > > ________________________________ > > On 14/12/2010 02:08, Ben Caradoc-Davies wrote: > > Andrew, > > there are technical barriers, such as the lack of support for parsing > complex GML features. WFS-T would require parsing complex features > before they could be inserted into a database. app-schema is build on > simple features, and so locking would have to be coordinated with these. > Furthermore, feature chaining would mean that related features would > also have to be locked. > > The biggest technical problem in my view is that CQL expressions are > used to implement polymorphism (conditionals) and to construct data in > the middleware. CQL expressions are in general irreversible. This is a > huge problem in using the existing mapping as it stands. So perhaps a > new mapping might be required? (Or a new ORM backend that addresses both > reversibility and efficiency in one go?) > > One conceptual hurdle is object identity and referential integrity. When > you update a complex feature, are you also updating nested properties, > or just the top-level feature? What about properties that are shared > between multiple features (associations)? What about multivalued > attributes: do you need to garbage collect to preserve foreign key > constraints? > > Sorry, I have more questions than answers. This is an interesting > problem. :-) > > Kind regards, > Ben. > > On 13/12/10 20:02, Andrew Chamberlain wrote: > > > Hi All, > > We were just sizing up the task of enabling transactions with the > app-schema plugin, and were wondering if anyone knew of any major issues > which might prevent / trouble the development of this? Questions which > immediately come to mind are: > > 1) Would the current mappings be re-usable, or would a separate set be > needed for the reverse (i.e. write) direction? > 2) Would such a reverse mapping be possible with the current mechanisms? > > I'm hoping that the original reason that transactions wasn't implemented > was simply a matter of limited time and funds, and not something technical. > > Any thoughts/pointers would be much appreciated. > > Best regards, > > Andy > > ------------------------------------------------------------------------------ > Oracle to DB2 Conversion Guide: Learn learn about native support for PL/SQL, > new data types, scalar functions, improved concurrency, built-in packages, > OCI, SQL*Plus, data movement tools, best practices and more. > http://p.sf.net/sfu/oracle-sfdev2dev > _______________________________________________ > Geoserver-users mailing list > [email protected]<mailto:[email protected]> > https://lists.sourceforge.net/lists/listinfo/geoserver-users > > > > > > > -- Ben Caradoc-Davies <[email protected]> Software Engineering Team Leader CSIRO Earth Science and Resource Engineering Australian Resources Research Centre ------------------------------------------------------------------------------ Lotusphere 2011 Register now for Lotusphere 2011 and learn how to connect the dots, take your collaborative environment to the next level, and enter the era of Social Business. http://p.sf.net/sfu/lotusphere-d2d _______________________________________________ Geoserver-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geoserver-users
