Service Modeling Language: Difference between revisions

Revision as of 01:53, 27 December 2006

Revision as of 06:13, 26 March 2007

Line 14:

:'''1.''' Models focus on capturing all invariant aspects of a service/system that must be maintained for the service/system to be functional. They capture as much detail as is necessary, and no more.

:'''2.''' Models are units of communication and collaboration between designers, implementers, operators, and users; and can easily be shared, tracked, and revision controlled. This is important because complex services are often built and maintained by a variety of people playing different roles.

:'''3.''' Models drive [[modularity]], [[Re-use]], and [[standardization]]. Most real-world complex services and systems are composed of sufficiently complex parts. [[Re-use]] and [[standardization]] of services/systems and their parts is a key factor in reducing overall production and operation cost and in increasing reliability.

:'''4.''' Models represent a powerful mechanism for validating changes before applying the changes to a service/system. Also, when changes happen in a running service/system, they can be validated against the intended state described in the model. The actual service/system and its model together enable a self-healing service/system – the ultimate objective. Models of a service/system must necessarily stay decoupled from the live service/system to create the control loop.

:'''5.''' Models enable increased automation of management tasks. Automation facilities exposed by the majority of IT services/systems today could be driven by software – not people – for reliable initial realization of a service/system as well as for ongoing lifecycle management.

Line 26 ⟶ 22:

:'''1. Schemas''' – these are constraints on the structure and content of the documents in a model. SML uses a profile of [[XML Schema]] 1.0 as the schema language. SML also defines a set of extensions to [[XML Schema]] to support inter-document references.

:'''2. Rules''' – are [[Boolean expression]]s that constrain the structure and content of documents in a model. SML uses a profile of [[Schematron]] and [[XPath]] 1.0 for rules.

Once a model is defined, one of the important operations on the model is to establish its validity. This involves checking whether all data in a model satisfies the [[XML Schema|schemas]] and rules declared.