Services and Data

A pretty good exposition of services and data within and across service bouindaries from Microsoft. Something is lacking though...

SQL makes a great tool for representing data on the inside of services. These strengths are inextricably linked to the bounded nature in both space and time of SQL, which make it fantastic for representing data on the "inside". Unlike XML, SQL has strong querying capabilities. SQL's makes comparisons between almost anything within the bounds of the database. Because of SQL's bounded nature, however, it is incapable of the strengths of XML in the "outside". SQL does not offer independent definition of schema as it depends heavily on a centralized and tightly coupled DDL.

What's wrong with this? It's out of focus.

At some point though developers will have to address data models as opposed to data notations. What are good models within and across service boundaries, whatever the notations used to representation and query? I have some ideas, but I'd like to see these ideas addressed more broadly and deeply.