XML Schema derivation by extension superfluous?. Don falls for derivation by restriction one more time. [Don Box’s Spoutlet]

While I was just trying to round out some ideas related to the schema and web services discussion we’ve been having, I came across this post from Don.  Very pertinent to what we’re talking about, relative to extending a schema when it contains xsd:any extensibility elements.

When we derive by restriction, we are guaranteed that any valid document matching the new schema will also validate against the original schema.  This is what I was trying to describe below…just not as succinctly as I might have.