Directory Entries

A directory entry is a set of attributes and their values. Every entry has an object class attribute, which specifies the kind of object the entry describes and defines the set of attributes it contains. For a given object class, some attributes are mandatory and some are optional. For example, the object class country is described by the mandatory attribute countryName, and the optional attributes description and searchGuide.

The schema defines the attributes that are mandatory and optional for an entry of a given object class. It also defines an inheritance hierarchy. All object classes inherit the characteristics of their superior object class. For example, the object class organizationalPerson is a subclass of the Person object class. It inherits the mandatory and optional attributes from the Person object class.

All object classes inherit from the object class top. The object class top contains the mandatory attribute objectClass. This ensures that all entries have an object class attribute.

There are two types of object classes: structural and auxiliary. A structural object class defines the type of entry. An entry can have only one structural object class. An auxiliary object class is not sufficient to define alone a type of entry, but can be specified in addition to a structural object class. For example, the auxiliary object class uidObject can be used to assign a uid to any entry in the directory.