In his recent interview with Jonathan Schwartz, Steve Gillmor makes the statement that “XSD [is] being baked into Office, but is being deprecated in favor of a new schema structure for WinFS.” This reflects some statements by Jon Udell. Dare had what I thought was a good response, and John Montgomery posted my opinion on this before I had my blog setup.
I'll say it as plainly as I can: the choice to not use XSD to describe WinFS types in no way deprecates the use of XSD to describe XML documents or data.
For a number of really good reasons we decided early on that the that first class things WinFS would store would be items, relationships, and extensions not XML elements and attributes. As such, we needed a language to describe our items, relationships and extensions. Trying to do this with XSD was sort of like trying to describe dance movement using the language of physics.
Sure, we could have used some sort of XSD + Annotations - Features We Can't Support. But this is also a bad idea and would result in other kinds of criticism. It is interesting that nobody is saying we should have used a modified SQL grammar (CREATE ITEMTYPE Foo ...).
I want to make one final point: even though the first class things stored in WinFS are not elements and attributes, we are working on a really good XML storage story for WinFS. With the emphasis of Office on XML, it would just be plain stupid for us to do anything else. Oh, and I also think it is what our customers will want.