ideas: technology
The Essence of Service Oriented Architecture

How can you use service oriented architecture (SOA) in actual developments? Exactly what do we do differently to what we did 20 years ago?
With this article I would like to give you a simple answer.
At the end of this article you will know basically what service oriented architecture is and how you can use it to reach your goals.
What is service oriented architecture (SOA)? At first I would like to give you a real word


example to show the difference between conventional solutions and service oriented architecture.
Let’s say you want to have an ancient book, what is quite rare. You can go into a second-hand bookshop and ask for the book. If it is not found, you can go into another until you find it.

This way you will surely spend some time and attention to have this book (if you find it).
Today you don’t do this anymore. You simply use an online service (google) to find bookstores with this book. Afterwards you use the online service of the bookstore, to get actual details and aviability of this book, then use a service again to order and pay for this book.
So you use online services to solve problems simpler and faster. This is the way SOA works.
In the business world there is a similar evolution:
1.The paper way: You create and print order, you send it. On the other side the order gets entered into system.
2.The file interface: You create an order. It gets written into a file. You send (upload) this file to your partner, where it gets processed.
3.Service oriented: You use an online service of your partner to get an actual catalog. You choose the items you want and you place your order within the other system.

What are the main advantages?
1. You have actual product information/condition to decide. You eliminate all the problems of
-updating your catalogs all the time,
-sending orders of obsolate or unavailable products,
-following each change in the partners system.


2. If you order this way, you are absolutely certain, that you successfully created a valid document in your partners system, what will be executed as an internal document. It will be not lost, overwritten, or misinterpreted by some interface.

Conclusion: If I would plan system architecture today, if possible, I would use an always actual online service instead of a conventional system with redundant data in files or tables. Of course SOA has many other parts and details – you can check out the references - but I find it very important to understand the essence, that everything is based on services.

SOA on
Enterprise SOA on
SOA defined by is a SOA platform!

Look at the other side as well (contra SOA)

Published on in 2004.