Fantastic paper from Pat Helland : Data on the Outside Versus Data on the Inside. In this paper, Pat gives a high-level overview of what SOA really means and all its implications.
His conclusions are not really groundbreaking:
- use version dependent identifier
- use XML for outside data
- use SQL for inside data
- use Objects for business logic
But what is great is the way he comes to that conclusion.
My favorite part is the introduction of a temporal notion in SOA. I never realized before that using SOA has implications both on space and time. And the analogy between Newton and Einstein laws and RPC/2PC and SOA is simply brillant.
This paper is a must for anyone interested in SOA without the hype surrounding the acronym (and not cluttered by a list of hundreds of WS-blablah).
I had the great pleasure to meet Pat Helland at HPTS'03 and I learned a lot by listening to him (and his songs!). He has the most amazing quality to make complex things simple to understand (is there any better description for 2PC protocol than calling it the "unavailibility protocol"?)