Schema Management: Introduction

The topic of LDAP schema's is a complex one. Volumes can be written about this topic but for the sake of keeping this simple we will discuss only the fundamentals of this subject.

The LDAP schema is primarily organized into 4 catagories.

Object Classes

Attrbitues

Syntax

Matching Rules

Objectclasses

An LDAP directory entry is a made up of one or more object classes. Object classes are used to group attributes together.

Attribtues

Attributes are the container elements that you assign data values to such as a persons first name, last name, password etc...

Syntax

Syntax is applied to the attribute establishing what data types can be stored in the attribute. For instance, a particular attribute might be used to store string or binary data etc...

Matching Rules

Matching Rules, a.k.a. Equality Rules, are a way of applying formatting rules to the Syntax/data types. For instance, the "cn" attribute a.k.a. "commonName" is typically used to store user credentials. The "cn" attribute has a matching rule of "caseIgnoreMatch". By applying the "caseIgnoreMatch" equality rule to the "cn" attribute, searches on the "cn" attribute are not case sensative. So if your searching the directory for an entry like "cn=John MacDonald" or "cn=john macdonald" you don't have to worry if your case spelling of the name is correct.