This documentation supports the 19.11 version of BMC CMDB, which is available only to BMC Helix subscribers (SaaS).

To view an earlier version, select the version from the Product version menu.

Modifying the data model by using Class Manager

Common Data Model (CDM) is the set of Configuration Item (CI) and relationship classes that ship with BMC CMDB. CDM is designed to be useful for almost every business scenario, but you can modify it by using Class Manager when you want to customize it for your business requirements. If a reason arises where you must extend the data model, you must create your own classes or extend a class with additional attributes.

As a configuration manager, you can use BMC CMDB Class Manager to define properties for Configuration Item (CI) and relationship classes. The properties of a class define the class and how it stores data.

This section contains information about the following tasks:

Use Class Manager interface to view CDM and extensions.Class Manager interface to view CDM and extensions

Understand the major steps required to create or modify classes by using Class Manager.

Defining class properties in Class Manager

Define the class properties in Class Manager, including the type, how the class stores data, and (for relationship classes) the relationship type.

Specify permissions. If you do not specify permissions for a class, BMC CMDB assigns default permissions.

Customize CDM by creating a CI and relationship class attributes.

Propagate attributes in a weak relationship. This step is necessary only if you have created a relationship class that has a weak relationship, and the attributes from one class should be propagated to another class. 

Specify indexes. Indexing can reduce database query time, so you must index attributes that you expect users to frequently use in queries.

Configure instance auditing for the class. Auditing enables you to track the changes made to instances of a class.
Understand the common CI relationship class propertiesCommon CI and relationship class properties
Understand the class attributes in Class Manager.Class attributes in Class Manager
Document your data model and its customization by creating an HTML version of your data model.Generating Help for the data model by using the cdm2html utility

Related topics

Modification of your data model

Learning about the common data model

Knowledge Article 000095846: Restoring missing common data model attributes from class hierarchy

Planning the data model

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