We’ve talked a bit before about CORBA and data transfers between disparate systems, but we haven’t talked specifically about web services. In general, they perform about the same functions, about 90% of the technologies overlap. In fact, much of the technologies utilized between ORB’s (Object Request Brokers) and Web Services are the same.
The difference is primarily in two key assumptions: In the web world, users and systems are available intermittently and users and systems must be able to find each other without knowing they even exist. Think about your relationship with Google or Yahoo. You log into the internet to make a call for a webpage in the form of a search. Google or Yahoo returns results to you, and you get your information prior to disconnecting your service.
OK – so Google is quite a different technology from web services, but the comparison is adequate. Let’s talk about the components of web services and what it means. We will simplify the discussion to two technologies. The first is XML. XML (extensible markup language) is basically a message that has been formatted to be readable by a destination supporting the same technology. SOAP (simple object access protocol) is the packaging for XML. Think about it this way: XML is your letter, and SOAP is the mail carrier. That’s about as simple as I can get it. We should note that SOAP is unidirectional.
Here are some very simple models:
One originator, one recipient
One originator, two recipients
Why is this important? You remember in the “vision” diagram I presented, that there is a web services layer. With that layer, employees, managers, vendors, applicants, contractors, and everyone else you can think of can access your systems through a single portal. (See the single sign-on discussion for more about how this works). It also allows you to more effectively manage how your systems “talk” to each other.
The critical piece in here is that data becomes an on-demand commodity.
Next Week: Web Services and Directory Access: Technologies Converge
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