While presenting tolog updates at TMRA 2009 I casually referred to the possibility of using tolog updates to create a trigger mechanism in Ontopia similar to triggers in relational databases. After the presentation the idea grew on me, and so I decided to elaborate a little further on it and present it in the open space session. The result was this little presentation, which gives a brief outline of the idea.

2 thoughts on “Triggers”

  1. IMO, the ability to use TM queries as a framework for defining “knowledge events” and “event triggers” is one of the most compelling aspects of TM technology. Particularly compelling is the ability to define knowledge events based on knowledge assets across multiple (otherwise independent) repositories.

    Back in the olden days of yore (i.e., the Elmer R&D project at Starbase), we built out this idea (on OKS) with very promising results–check out slides 5-7:

    I love the idea of rolling event detection right in the Ontopia core, but I would suggest that the registered knowledge event handlers should be totally general purpose—abstracted away behind an KnowledgeEventHandlerIF and KnowledgeEventHanderFactoryIF framework. One such handler could be a tolog update processor, but it should be possible to execute arbitrary code, make web service calls, etc. It should be possible to chain handlers together and control how events bubble along the chain.

  2. Interesting that you are so much in favour of this, but now that I see your slides again I can see why. This really is quite close to your idea of knowledge events. Reception was generally quite positive in Leipzig, too, so this probably is worth doing, especially as it is so simple to implement.

    The guys from Morpheus had the same comment as you, that while being able to attach tolog update statements is good, being able to trigger general Java calls is better. And I have to agree. I was too focused on tolog updates when I presented this, probably because that’s where the idea came from.

    We’ll think about this some more and see what we can do.

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