CIM Concept 

The Common Information Model (CIM) is a standard of the Distributed Management Task Force (DMTF) and is based on the object-oriented modeling approach. This standard provides a neutral implementation schema to describe management information within a computing environment. For more information about CIM and DMTF, see www.dmtf.org.

Object-oriented modeling is a means of representing the real world. CIM is designed to model hardware and software elements. The following are basic terms associated with this concept:

·        Class and inheritance

·        Instance

·        Association and reference

·        Schema

Class and Inheritance

A class is a collection of objects that have similar properties. It is a template for a type of object. CIM supports the inheritance concept so that classes in the context of CIM are organized hierarchically.

Inheritance is an object-oriented concept. A class automatically has all the properties of the class from which it is derived. The class that passes on properties is called the superior class. The class that inherits properties from a superior class is called the subclass. A subclass represents a specialization of the superior class by enhancing it with additional properties.

There are also abstract classes. These are classes that do not have a particular form, but which represent the superior class for one or more subclasses.

Example

The CIM class SAP_Product defines the number of SAP products that have joint properties such as the same product name, version, and so on.

Instance

An instance is a form of a class, or an object of the class. All properties defined in the class have fixed values in an instance.

Example

The CIM class SAP_Product can have instances such as mySAP CRM and R/3 Enterprise.

Property and Key Property

An instance has certain properties. A class declares some of these properties as key properties. The CIM concept uses key properties to clearly identify instances of a class. This identification is also known as the name of an instance. This means that there are no two instances of one class whose key properties are completely identical. Key properties are mandatory for any given instance.

Example

The CIM class SAP_ProductLine declares Vendor and Name as key properties. In addition, this class also has properties such as Caption and Description. The product CRM IPC differs completely from other products with the name sap_productline.name="CRM IPC",vendor="sap.com" .

Qualifier

Qualifiers contain metainformation that describes classes, instances, and properties in more detail.

Example

Many CIM classes or their instances have a Caption property. This property is a short description and has, among other things, a maxlen qualifier, which restricts the length of the description to 64 characters.

Association and Reference

Associations are a type of class that represent relations between classes or their instances. An association has one or more references as properties, which refer to corresponding CIM instances. In this way you can define relations between classes or their instances, without affecting the definitions of the classes concerned.

Example

The association class SAP_ApplicationSystemHost represents the connection between a computer (hardware) and the SAP system (software) running on this computer.

Schema

A schema in CIM is a collection of classes and has a name. You use a schema to name a class. A CIM class can belong to one schema only. You name a schema, class, and property in CIM by using the syntax schemaname_classname.propertyname.

The CIM standard contains a number of class definitions that represent the common model. This common model is called the CIM schema. You can extend this common model by adding technology-specific class definitions. These extensions are referred to as extension schemas.

Example

All CIM classes in the examples above belong to the SAP extension schema, which represents an enhancement of the CIM schema.