HP WBEM Services Software Developer's Kit for HP-UX Provider and Client Developer's Guide A.01

Schema Design and Implementation
Schema Design
Chapter 332
Strategies for identifying client-use models include:
• Consider one or more client use cases or scenarios (potential clients
may be GUI-based tools or CLIs).
• Identify which information needs to be provided.
• Determine which actions must be performed.
• Determine logical groupings of the information/actions.
In addition, one may need to consider how the client-use model would be
affected if the schema is hosted on several heterogeneous platforms.
Early scoping of the model to the target platforms assists in achieving
interoperability, a high-level goal of WBEM. Clients would then be able
to use common access schemes to obtain the information from all
platform types. The information derived from these analyses serves as a
basis for creating a draft object model.
STEP 2: Draft Object Model
An analysis of managed objects entails identifying the objects and
determining relationships between them. There are several types of
objects that should be considered in designing a schema, including:
• Managed Elements are the most commonly considered objects.
They are used to track the state of some managed entity and perform
changes as required. Examples uses of these include devices,
systems, and software elements.
• Associations are objects which relate two other objects. (Note that
CIM associations can also have their own properties.) An example
use of associations is to represent the relationship between a device
driver and its associated device.
• Aggregations are a special type of association, with the notion that
an object is made up of an aggregation of some number of other
objects. For example, various logical devices can be aggregated to
make up a complete computer system.
• Services are objects describing services and service access points
implemented by managed elements. An example use is a print
spooler service associated with a printer.
• Settings are a description of settings for managed elements. An
example use is representing the kernel parameters associated with
an operating system;