--- Anne Thomas Manes <[EMAIL PROTECTED]> wrote: > Stuart said: > > The thought that XML is a "data model" on > > par with the relational model is rather laughable. XML is about > > interchange, it says nothing about data management. Yet I do see > some > > misunderstandings and desires to redo enterprise modeling efforts, > this > > time with XML Schema. (shudder) > > > I must disagree with you here. While I agree that typically XML > documents aren't stored in perpetuity (or at least as long as relational data > tends to be), I do believe that if you want to enable sharing an reuse, you > need to define standard representations of important data types, .e.g., > "customer", "order", "purchase order", etc, for use in messages. The idea that > you would let your developers generate a few dozen nearly identical (but still > incompatible) versions of "customer" is crazy.
I may have misspoken. 1. I do think canonical schemas are very useful. 2. My point is that I do not think that XSD offers any guidance about data management. (e.g. normalization, referential integrity, etc.) Though, in large enterprises, it's quite hard to have a canonical schema for "Customer" (having been through a couple customer-centric projects with both data warehouses and SOA). Marketing has a different definition from finance. And besides, one already has many different customer databases, and different definitions of customer, since different lines of business were allowed to operate autonomously. Approaches like "customer data hubs" have been a mixed success. Of course, one should try. ;-) Stu ____________________________________________________________________________________ Don't pick lemons. See all the new 2007 cars at Yahoo! Autos. http://autos.yahoo.com/new_cars.html
