Each of the classes in your information model exposes one or more interfaces. Add a new interface to a class by creating an instance of the InterfaceDef class.
To create a new interface definition
Be sure the interface identifier that you supply as an input parameter to this method matches the GUID that has been assigned to the interface.
Note Among the interfaces you create for your information model, you must include an interface that the ReposRoot class implements. You need this interface and an attendant relationship type to enable navigation to the objects that will populate your information model. (See Information Model Creation Issues for more information about why you need this interface.)