Jama Poulsen:
Has Ruby on Rails (http://www.rubyonrails.com) been considered for Wikidata? (from looking trough the Meta discussion page it seems this is not the case)
I've actually been hacking on a RoR app when Gerard came over here. He had to drag me back screaming to work on Wikidata again. ;-) RoR is beautiful indeed, in many ways (ugly in some), but the only way it would be useful for Wikidata is if we implemented WD from scratch as something separate of MediaWiki. That makes a limited amount of sense, since our primary intended deployment are the Wikimedia projects.
We have considered using RoR to hack together some prototypes, but have for now decided against it as we want to avoid further delays that would be caused by throwaway code.
I am, however, trying to learn from RoR in that I want to come up with some clever conventions for table and column names that can lead to very quick deployment of simple applications, including applications which require relations between tables. However, complex Wikidata applications will need quite a bit of specialized coding, for which we're currently contemplating a "hooks" model similar to the one used for extensions.
The Wikidata integration into MediaWiki is intended to be very deep. The simplest Wikidata application would be a regular MediaWiki edit page which, in addition to the normal text field, would have some other edit field, say a date (this could be useful for Wikinews, for example).
In practice, Wikidata will require creating new tables with these desired characteristics, which will then be hooked up to a namespace (hence the current focus on namespace-related work). I've decided against a fixed table model because I considered it not scalable for complex applications, so a Wikidata table always corresponds to a real table in the database (with some required minimum fields for versioning the table and connecting it to a wiki page). Another advantage of this approach is that specialized tools like phpMyAdmin can be used to design the gist of the application.
I will publish my design specifications soon. This will also include some more details about "Ultimate Wiktionary", which is really the main thing we're working towards -- an incredibly complex and powerful application built with Wikidata (and, very likely, tons of specialized code). I hope that when we have these semi-final specs, we can put an end to much speculation. By the end of the year, we also want to have a prototype that demonstrates much of Wikidata as well as some functionality that will be in Ultimate Wiktionary.
My main challenge at the moment is to find a scalable model for versioning multiple tables with complex relations between them. Versioning is necessary for the "wiki" in "Wikidata", but at some level of complexity, it gets very tricky.
If anyone is interested in working on Wikidata, please contact me again (you may have done so before - sorry if something fell through). We're making substantial progress and are also exploring new sources of funding for future development.
Best,
Erik