Preface

This book is the official documentation of PostgreSQL™. It has been written by the PostgreSQL™ developers and other volunteers in parallel to the development of the PostgreSQL™ software. It describes all the functionality that the current version of PostgreSQL™ officially supports.

To make the large amount of information about PostgreSQL™ manageable, this book has been organized in several parts. Each part is targeted at a different class of users, or at users in different stages of their PostgreSQL™ experience:

PostgreSQL™ is an object-relational database management system (ORDBMS) based on POSTGRES, Version 4.2, developed at the University of California at Berkeley Computer Science Department. POSTGRES pioneered many concepts that only became available in some commercial database systems much later.

PostgreSQL™ is an open-source descendant of this original Berkeley code. It supports a large part of the SQL standard and offers many modern features:

  • complex queries
  • foreign keys
  • triggers
  • updatable views
  • transactional integrity
  • multiversion concurrency control

Also, PostgreSQL™ can be extended by the user in many ways, for example by adding new

  • data types
  • functions
  • operators
  • aggregate functions
  • index methods
  • procedural languages

And because of the liberal license, PostgreSQL™ can be used, modified, and distributed by anyone free of charge for any purpose, be it private, commercial, or academic.