Extending the Schema

Microsoft® Active Directory™ schema defines the attributes and classes that can be used in Active Directory. The base schema that ships with the system contains a rich set of class definitions, such as user, computer, and organizationalUnit, and attribute definitions, such as userPrincipalName, telephoneNumber, and objectSid. The existing set of classes and attributes should meet the needs of most applications. However, the schema is extensible, which means that you can define new classes and attributes.

This section discusses extending the Active Directory schema, including the following topics:

• How to bind to the schema container and read the properties of existing classes and attributes.
• How and when to extend the schema by defining new attributes and classes.
• How to install schema extensions using LDIFDE, CSVDE, or programmatically with ADSI.

For an overview of the Active Directory schema including information about the schema implementation, class definitions, and attribute definitions, see Active Directory Schema.

For reference pages for the predefined schema classes, attributes, and attribute syntaxes, see the Active Directory Schema Reference in the Active Directory Reference.