How to Version Schemas?

Version and source control for schemas and schema objects is badly needed by us all, especially in complex, multi-enterprise development situations. This paper describes how to support true versioning of schemas and fine-grained schema objects. An important conclusion is that schema evolution and schema development are essentially synonymous, in that the applicable techniques and requisite technology are the same for both.

http://www.idealliance.org/proceedings/xml04/papers/74/howToVersionSchemas.html#S1.