Web Table 1: Supported Schema Operations on classSchema Objects
Attribute	Function	Mandatory	Reusable in Win2K	Reusable in Windows 2003	Comment
Cn	Contains the object’s common name	Yes	No; the cn must be unique and can’t be renamed in Win2K	Yes, in Windows Server 2003 forest functional level and only if the old classSchema object’s cn is renamed	Any new classSchema object must use a unique cn in the Schema Naming Context (NC).
governsId	Contains the object's OID	Yes	No, even if the old schema classSchema object is deactivated	Yes, in Windows Server 2003 forest functional level and only if the old classSchema object is deactivated	Any new classSchema object must use a unique OID.
objectClassCategory	Defines the object's class type (i.e., structural, abstract, or auxiliary)	Yes	Yes; you can recreate the same object class with the same objectClassCategory if the old classSchema is deactivated	Yes; you can recreate the same object class with the same objectClassCategory if the old classSchema definition is deactivated	This attribute's value can be defined only when the classSchema object is created.
lDAPDisplayName	Defines the LDAP display name of the class (e.g., "user")	Yes	Yes, if the old classSchemaObject's lDAPDisplayName is renamed and only for Category 2 objects (a schema extension always creates Category 2 schema objects)	Yes, for Category 2 objects only; in non–Windows Server 2003 forest functional level, if you plan to recreate a classSchema object using the same lDAPDisplayName, you must change the lDAPDisplayName of the old schema object before deactivating it. No restrictions for Windows 2003 running in forest mode.	Any new schema object must use a uniquelDAPDisplayName.
schemaIDGUID	Contains the object's GUID; use this attribute only if you plan to create extended rights (also called Control Access Right objects). See http://msdn.microsoft .com/library/en-us/ad/ad/control_ access_rights.asp	No	Yes, if the old classSchema object is deactivated	Yes, if the old classSchema object is deactivated	Any new classSchema object must use a unique schemaIDGUID if used.