Realationship enterprise service - application/entity service

Question

I read some books about ESA and CAF but I still don't know the relationship between enterprise services in ESA and application and entity services in the Netweaver DevStudio (CAS framework).
Are application/entity services also enterprise services? Or is there a difference?
Thanks for your answers.
Joachim

Answer 1

You can consume SAP Enterprise Services. You can also participate in the definition of the Enterprise Services  through the ES Community (see ES Community under Enterprise SOA in SDN) and even create your own Enterprise Services. You can use whatever web development tools you like. In Netweaver Java stack, you can use CAF to implement or develop Application Services (where business logic is coded) leveraging Entity Services taping into your local or remote data model(s). Enterprise Services can be modeled and coded in CAF Application Services but you can use plain J2EE as well. In SAP case, the interfaces for Enterprise Services are defined in XI (input/output/exception). Their implementation happen in the appropriate SAP solutions like ERP where business logic can execute against appropriate data.
Practically CAF Entity Services cannot be called Enterprise Services unless you want to. They just perform basic CRUD (create/read/update/delete) operations on an data object. They're more like utility services. But like Anton's mention of "Private Enterprise Services", what's private remains your own business!