My literature teacher in the 7th grade has told the class one day a story about her days in as a university student; one of the literature classes in the university has been dedicated to Agnon, the only Hebrew writer who received Nobel Prize in Literature (Agnon's picture is in the left hand side). One of the famous stories of Agnon has a dog (such as the one in the right-hand side) as its hero; thus, the class of students at the university had discussed this story and had a debate about what does the dog represents, one group of students thought that dog is a symbol for Agnon itself, and one thought that the dog is a symbol for the entire Jewish people. Since Agnon was still alive those days, they have decided to send a couple of students to meet Agnon, set up a meeting in his house (well - Email questions were not on the radar at that time), and explained the dilemma - what does the dog represent? Agnon was somewhat amused to hear about the debate, and told them briefly - "I don't know what you are talking about, the dog represents a dog".
Going back for the childhood Reminiscences to the contemporary issues - I have read with interest the recent blog of Paul Vincent about "CEP vs. Business Rules" in which he mentioned me by reference (and not by name) saying: "Others seem to downplay the idea of rules for CEP". I have a substantial respect for Paul, and generally agree with most of the assertions he made in that blog. Let me add some more insights into this issue - I am using this blog to reflect about event processing, and make the point the "event processing" is a discipline that stands on its own feet, and is not a footnote to anything else - be it databases or business rules.
CEP functionality can indeed be implemented in either SQL or in an extension to business rule language as some of the vendors successfully demonstrated. It can also be implemented in half a dozen different ways (at least). Since I am trying to investigate "event processing" as a discipline, and not a specific implementation, thus is the play, and indeed I downplay specific implementations for now, and try to think on the fundamental issues. I may return in future blogs to talk about what type of implementations fit different types of functions/applications - which is a difficult question, and I don't really see that there is an issue of "CEP vs. Business rules" as these are conceptually orthogonal issues (and I agree that in practice there are various relations), and Paul's blog does a tremendous job of highlighting the differences and relations between the two.
For now - my dog is "event processing" and it represents "event processing" and not other concepts that are not fundamentally necessary to understand what "event processing" is.
More - Later.