A useful feature of schema-based directory services is the ability of administrators to add properties to objects. For example, administrators at the "ABX" organization might want to create an "ABXuser" based on the standard Active Directory user object, which contains additional properties useful at ABX.
Assume that ABX wants to add a Card Key number to the user object, and call the new object type "ABXuser." Active Directory makes this simple. First, a new class is created in the SCHEMA container, and is marked as derived from the desired base class. New properties are added to the new Class. The Visual Basic code to perform this extension appears below.
Example 7: Extending the Schema
Dim schema as IOleDsSchema
Dim user as IOleDsClass
Dim ABXuser as IOleDsClass
Dim CardKey as IOleDsProperty
' bind to the schema container
set schema = GetObject("@NS!ABX\Schema")
' get the base user object to derive from
set user = GetObject("@NS!ABX\Schema\user")
' create a new class in the schema
set ABXuser = schema.create("class","ABXuser")
' set the properties of the new class - we don't want to override the base
' object, so we copy the base object's properties
ABXuser.CLSID = user.CLSID
ABXuser.PrimaryInterface = user.CLSID
ABXuser.Container = False
ABXuser.DerivedFrom = user.PrimaryInterface
ABXuser.Containment = user.Containment
' write out the new class
ABXuser.SetInfo
'create a new property in the class
set CardKey = ABXuser.create("property","CardKey")
CardKey.syntax = "Bstr"
CardKey.SetInfo
'Done!