Service layer vs business layer - differences?

Question

I have been doing a lot of reading on service layers and business layers and how they compare. I have a read a number of the threads here on StackOverflow on the topic and i still find myself confused as to the differences between the two if there are any. To me it seems that its mainly a naming convention where one dev calls the middle layer a business layer and another may call it a service layer. From the code i have seen here on SO and around the web they seem to do mainly the same thing - that is query the repository, maybe do some filtering and/or validation and return the results to the presentation layer. So can anyone clarify the differences between the two? Or am i missing the mark in my assesment?

I am working with EF, MVC 3 and VBNET, FYI

Answer 1

In our projects we often have the following structure:

Service layer:

• Publishes the Service Endpoint (this could be your MVC web page, or a WCF endpoint)
• Does a security check
• Maps data from contract data transfer objects to business objects
• Calls functionality in the business layer

Business layer

• Contains business logic
• Accesses the data layer (this could be your entity framework data model)