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

Client Implementation
Navigating Schema
Chapter 5 93
Navigating Schema
An important consideration in client design is what methodologies will
be used in navigating the schema presented by CIM servers on various
managed platforms. A correct understanding of the use of keys and
associations in schema navigation can facilitate greater efficiency and
performance of client/server interactions as well as enabling
interoperability across heterogeneous managed systems.
Keys
Specific objects, or instances of classes, are accessed through the use of
keys. Keys are identifiers that uniquely define instances within a
namespace. A particular class's key can be made up of one or more key
properties.
Qualifiers for Classes with Keys
A key property has all the characteristics of any other property in a CIM
class, only with the additional semantics associated with having the Key
qualifier. These characteristics of a property include that its related
qualifiers are inherited by all subclasses. The combination of all key
properties defined for a class makes up the compound key for the class.
The following example MOF fragment shows a class definition for the
class CIM_OperatingSystem where the combination of properties
CSCreationClassName, CSName, CreationClassName, and Name (the key
properties) makes up the key of the class.
Example 5-1 Abridged MOF declaration of CIM_OperatingSystem
// ========================================================
// OperatingSystem
// ========================================================
class CIM_OperatingSystem : CIM_LogicalElement {
[Propagated ("CIM_ComputerSystem.CreationClassName"),
Key, . . . ]
string CSCreationClassName;
[Propagated ("CIM_ComputerSystem.Name"), Key, . . . ]
string CSName;
[Key, . . . ]
string CreationClassName;
[Override ("Name"), Key, . . .]