Difference between SOA & ESA

Question

Hi,
Can someone explain the brief concept of ESA.
I know there are lot of links wrt this information, i want to know what is the specific difference between SOA & ESA, functionally and technically?
Thanks a lot ..
Regards,
Charu

Answer 1

Hi
In a nutshell, ESOA are simply Web services that provide enterprise-level business functionality.They may range from very simple lookup services (like finding a company’s location or product offerings) to more complex and composite services — but what they have in common is that they’re highly integrated into your process or application.Typically ESOA are high-level components that take more granular Web services and aggregate them into reusable elements with business value. For example, take the service Cancel Purchase Order. An elementary Web service like Delete Purchase Order would simply lead to the deletion of a purchase order in the corresponding database. However, if the stated goal is “cancel purchase order,” the service has to become a more far-reaching enterprise service that handles this process end-to-end, and therefore has to trigger a number of follow-up actions, including:
=> Check against production orders
=> Check against a corresponding billing process
=> Update of inventory/warehouse information Or consider the Credit Limit Check
service, which at first glance seems to be quite simple. Normally, this service is one ingredient of the Order Creation service. But typically, credit checking is
really a more elaborate composite service.
5 Key Principles of ESOA
1. Abstraction — hiding confusing details
2. Modularity — breaking down complexity, resulting in reusable pieces
3. Standardized connectivity — enabling flexible composition of services to
create bigger processes and scenarios
4. Loose coupling — allowing for separate evolution of the various components
without breaking any points of integration
5. Incremental design — enabling changes to composition and configuration
without affecting the interior of components, and vice versa
Regards,
Satyendra