2008/10/20 Kirstan Vandersluis <[EMAIL PROTECTED]>: > --- In [email protected], Michael > Poulin <[EMAIL PROTECTED]> wrote: >> >> a single canonical viewacross an enterprise may exist but not used > (this is what I think Steve meant) >> - Michael >> >> >> >> ----- Original Message ---- >> From: Steve Jones <[EMAIL PROTECTED]> >> To: [email protected] >> Sent: Saturday, October 18, 2008 3:04:11 PM >> Subject: Re: [service-orientated-architecture] Re: van Hoof on EDA > & SOA >> >> >> Depends what you mean by canonical. IME a single canonical view >> across an enterprise is pretty much IT suicide. >> >> Steve >> > > An enterprise should have a common data dictionary, at a minimum > defining the terms and structures shared across groups. But I'm > really relating back to Paul's note that the message defines a > structure using XML Schema, and that structure is "cannonical" in > that any user of the service conforms to it in order to use the > service. I would say this message structure should be part of the > enterprise data dictionary and reused as appropriate. In this way, > its use as a cannonical model could be broader than just as a > message set.
Now the first bit I agree with (service defining a specific interface that people must use) the second (that interface should be standardised at the enterprise level) I disagree with. Take "Customer", if I am sending an order to a customer I need to know 1) Name 2) Address 3) What I'm shipping So the "Shipping" Service needs to have just that, it doesn't need the enterprise canonical form of customer that also includes Last contact Buyer history Credit History Credit Rating Mother's Maiden name Pet name Sales contact Phone number etc etc etc This is why I don't advise enterprise canonical models except to say that "minimal canonical form" is a good idea. Steve > > -Kirstan > >> 2008/10/17 Kirstan Vandersluis <[EMAIL PROTECTED] com>: >> > --- In service-orientated- architecture@ yahoogroups. com, > Michael >> > Poulin <m3poulin@ .> wrote: >> >> >> >> Yes, it was deliberate overstatement though based on OASIS SOA > RM >> > standard. >> >> When I talk with people who see value in SOA Projects, I usually >> > one of two cases (sometimes, both): >> >> 1) it is just an initial first pilot project 'to taste the > water', >> > and it is OK >> >> 2) Web Services are used for application integration w/o going >> > into real SOA value of business functionality >> >> >> >> Actually, I do not mind having SOA projects but only AFTER the >> > overall business functionality picture and SOA environment are in >> > place: think/see globally and move locally. >> > >> > Yes, thinking globally and acting locally boils it down nicely. > But >> > the reality is there is so much project-level development going > on >> > that the project group can't wait around for a global SOA > intiative, >> > if one even exists. So what advice would you give them? I would >> > say Paul's advice, along with his 4 point clarification, is a > good >> > start. In a nutshell, define common messages as the basis of the >> > interface for an endpoint, using XML Schema, with an eye towards >> > using or building a canonical model (e.g. a "Customer"). Without >> > this guidance, you'll end up with JBOWS with little or no reuse > and >> > agility, and you'll add to the chaos that will have to be fixed >> > eventually. >> > >> > -Kirstan >> > >> > >> >> >> __________________________________________________ >> Do You Yahoo!? >> Tired of spam? Yahoo! Mail has the best spam protection around >> http://mail.yahoo.com >> > >
