<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Preface</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REV="MADE" HREF="mailto:pgsql-docs@postgresql.org"><LINK REL="HOME" TITLE="PostgreSQL 8.0.11 Documentation" HREF="index.html"><LINK REL="PREVIOUS" TITLE="PostgreSQL 8.0.11 Documentation" HREF="index.html"><LINK REL="NEXT" TITLE="A Brief History of PostgreSQL" HREF="history.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="stylesheet.css"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=ISO-8859-1"><META NAME="creation" CONTENT="2007-02-02T03:57:22"></HEAD ><BODY CLASS="PREFACE" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="5" ALIGN="center" VALIGN="bottom" >PostgreSQL 8.0.11 Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="index.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="index.html#AEN3" >Fast Backward</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="tutorial.html" >Fast Forward</A ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="top" ><A HREF="history.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="PREFACE" ><H1 ><A NAME="PREFACE" ></A >Preface</H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT ><A HREF="preface.html#INTRO-WHATIS" >What is <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN >?</A ></DT ><DT ><A HREF="history.html" >A Brief History of <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN ></A ></DT ><DT ><A HREF="notation.html" >Conventions</A ></DT ><DT ><A HREF="resources.html" >Further Information</A ></DT ><DT ><A HREF="bug-reporting.html" >Bug Reporting Guidelines</A ></DT ></DL ></DIV ><P > This book is the official documentation of <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN >. It is being written by the <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > developers and other volunteers in parallel to the development of the <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > software. It describes all the functionality that the current version of <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > officially supports. </P ><P > To make the large amount of information about <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > 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 <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > experience: <P ></P ></P><UL ><LI ><P > <A HREF="tutorial.html" >Part I</A > is an informal introduction for new users. </P ></LI ><LI ><P > <A HREF="sql.html" >Part II</A > documents the <ACRONYM CLASS="ACRONYM" >SQL</ACRONYM > query language environment, including data types and functions, as well as user-level performance tuning. Every <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > user should read this. </P ></LI ><LI ><P > <A HREF="admin.html" >Part III</A > describes the installation and administration of the server. Everyone who runs a <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > server, be it for private use or for others, should read this part. </P ></LI ><LI ><P > <A HREF="client-interfaces.html" >Part IV</A > describes the programming interfaces for <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > client programs. </P ></LI ><LI ><P > <A HREF="server-programming.html" >Part V</A > contains information for advanced users about the extensibility capabilities of the server. Topics are, for instance, user-defined data types and functions. </P ></LI ><LI ><P > <A HREF="reference.html" >Part VI</A > contains reference information about SQL commands, client and server programs. This part supports the other parts with structured information sorted by command or program. </P ></LI ><LI ><P > <A HREF="internals.html" >Part VII</A > contains assorted information that may be of use to <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > developers. </P ></LI ></UL ><P> </P ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="INTRO-WHATIS" >What is <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN >?</A ></H1 ><P > <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > is an object-relational database management system (<ACRONYM CLASS="ACRONYM" >ORDBMS</ACRONYM >) based on <A HREF="http://s2k-ftp.CS.Berkeley.EDU:8000/postgres/postgres.html" TARGET="_top" > <SPAN CLASS="PRODUCTNAME" >POSTGRES, Version 4.2</SPAN ></A >, 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. </P ><P > <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > is an open-source descendant of this original Berkeley code. It supports a large part of the SQL:2003 standard and offers many modern features: <P ></P ></P><UL COMPACT="COMPACT" ><LI ><SPAN >complex queries</SPAN ></LI ><LI ><SPAN >foreign keys</SPAN ></LI ><LI ><SPAN >triggers</SPAN ></LI ><LI ><SPAN >views</SPAN ></LI ><LI ><SPAN >transactional integrity</SPAN ></LI ><LI ><SPAN >multiversion concurrency control</SPAN ></LI ></UL ><P> Also, <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > can be extended by the user in many ways, for example by adding new <P ></P ></P><UL COMPACT="COMPACT" ><LI ><SPAN >data types</SPAN ></LI ><LI ><SPAN >functions</SPAN ></LI ><LI ><SPAN >operators</SPAN ></LI ><LI ><SPAN >aggregate functions</SPAN ></LI ><LI ><SPAN >index methods</SPAN ></LI ><LI ><SPAN >procedural languages</SPAN ></LI ></UL ><P> </P ><P > And because of the liberal license, <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > can be used, modified, and distributed by everyone free of charge for any purpose, be it private, commercial, or academic. </P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="index.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="history.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >PostgreSQL 8.0.11 Documentation</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" > </TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >A Brief History of <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN ></TD ></TR ></TABLE ></DIV ></BODY ></HTML >