The Directory Server Access Control Model
Understanding the Directory Server Schema
Matching Rule Description Format
Understanding Attribute Syntaxes
The Attribute Syntax Description Format
Commonly Used Attribute Syntaxes
Attribute Type Description Format
Object Class Description Format
Directory Server Object Class Implementation
Understanding DIT Content Rules
DIT Content Rule Description Format
DIT Content Rule Implementation
Understanding DIT Structure Rules
DIT Structure Rule Description Format
DIT Structure Rules and Multiple Schemas
DIT Structure Rule Implementation
Understanding Matching Rule Uses
Matching Rule Use Implementation
Understanding Directory Server Plug-Ins
Matching rules are used by the directory server to compare two values for the same attribute, that is, to perform matching operations on them. There are several different types of matching rules, including:
These matching rules are used to determine whether two values are logically equal to each other. Different implementations of equality matching rules can use different criteria for making this determination (for example, whether to ignore differences in capitalization or deciding which spaces are significant).
These matching rules are used to determine the relative order for two values, for example, when evaluating greater-or-equal or less-or-equal searches, or when the results need to be sorted.
These matching rules are used to determine whether a given substring assertion should match a particular value. A substring assertion is composed of at least one element from the following sets: at most one subInitial element, zero or more subAny elements, and at most one subFinal element.
These matching rules are used to determine whether two values are approximately equal to each other. This is frequently based on “sounds like” or some other kind of fuzzy algorithm. Approximate matching rules are not part of the official LDAP specification, but they are included in the directory server for added flexibility.