PostgreSQL 7.3.5 Documentation
PrevNext

Chapter 14. Interfacing Extensions To Indexes

Table of Contents
14.1. Introduction
14.2. Access Methods and Operator Classes
14.3. Access Method Strategies
14.4. Access Method Support Routines
14.5. Creating the Operators and Support Routines
14.6. Creating the Operator Class
14.7. Special Features of Operator Classes

14.1. Introduction

The procedures described thus far let you define new types, new functions, and new operators. However, we cannot yet define a secondary index (such as a B-tree, R-tree, or hash access method) over a new type, nor associate operators of a new type with secondary indexes. To do these things, we must define an operator class for the new data type. We will describe operator classes in the context of a running example: a new operator class for the B-tree access method that stores and sorts complex numbers in ascending absolute value order.

Note: Prior to PostgreSQL release 7.3, it was necessary to make manual additions to pg_amop, pg_amproc, and pg_opclass in order to create a user-defined operator class. That approach is now deprecated in favor of using CREATE OPERATOR CLASS, which is a much simpler and less error-prone way of creating the necessary catalog entries.

PrevHomeNext
Rules versus TriggersUpAccess Methods and Operator Classes