CMDB Common Data Model

The Common Data Model unifies the representation of configuration data. It is designed to store data (such as hardware information, service management information, people information), and provide a mechanism for linking that information to provide a complete view of how all elements of a company are tied together and affect each other.

The Common Data Model uses an object framework API to define the data model. The following table defines some commonly used terms needed to understand the data model.

Term	Description
Class	Data storage element. In database terms it relates to a table in the database, or a form in AR System. For example, the Computer System class in the CDM is a class that stores information about computer systems.
Attribute	Attributes are found within a class. An attribute is related to a column in a table or a field on a form in AR System terms. For example, the Computer System class has attributes that track the name, manufacturer, model, and so on, of the computer system.
Subclass	A subclass extends the definition of a class. For example, some features are included in the whole class, but there might be extra features (subclasses) that are added to the basic feature list. For example, the Computer System class is subclassed as a MainFrame class. The Mainframe class contains all of the attributes of the Computer System class, plus attributes that are specific to mainframes.
Relationship	Relationships are ways to tie two instances of data or configurable items together.