* Access control: what rights are available, how do you assign rights to
  authenticated users
* Indexing
* Defining database schema; optional/required, multivalued attributes,
  matching syntax

Auxilliary object classes

A class cannot be derived from more than one other class - in the language of object-oriented programmers, there is no "multiple inheritance".

However, it is quite possible for an entry to belong to more than one objectclass at a time.