SOA Service Granularity
By crupi on Pri 19, 2005
As you can see, this is a pretty poor definition. So, I thought about it and discussed it with Danny Malks and tried to make it more SOA-like. So, I started talking more about SOA services as business services and thus having business service granularity. Sounds a bit subtle, but has a strong intent. As I mentioned in a prior blog, we want SOA to take a top-down (problem to architecture to solution) approach. This means that the business unit (user) drives the requirements and essentially (but, not directly) the service granularity. So, one way to think about a SOA business service is to be able to put it in business speak. For example, we may talk about the Insurance Quote Service and Inventory Service. We can talk to business people about services using this granularity and not get into tech speak. Notice that we refer to the services as nouns, not verbs. I've seen many services defined by a verb, such as Add Employee Service. Focusing on the actions (verbs) rather than the service (nouns) creates fine grained services and should be avoided.