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<!-- doc/src/sgml/intro.sgml -->
<preface id="preface">
<title>Preface</title>
<para>
This book is the official documentation of
<productname>PostgreSQL</productname>. It has been written by the
<productname>PostgreSQL</productname> developers and other
volunteers in parallel to the development of the
<productname>PostgreSQL</productname> software. It describes all
the functionality that the current version of
<productname>PostgreSQL</productname> officially supports.
</para>
<para>
To make the large amount of information about
<productname>PostgreSQL</productname> 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
<productname>PostgreSQL</productname> experience:
<itemizedlist>
<listitem>
<para>
<xref linkend="tutorial"/> is an informal introduction for new users.
</para>
</listitem>
<listitem>
<para>
<xref linkend="sql"/> documents the <acronym>SQL</acronym> query
language environment, including data types and functions, as well
as user-level performance tuning. Every
<productname>PostgreSQL</productname> user should read this.
</para>
</listitem>
<listitem>
<para>
<xref linkend="admin"/> describes the installation and
administration of the server. Everyone who runs a
<productname>PostgreSQL</productname> server, be it for private
use or for others, should read this part.
</para>
</listitem>
<listitem>
<para>
<xref linkend="client-interfaces"/> describes the programming
interfaces for <productname>PostgreSQL</productname> client
programs.
</para>
</listitem>
<listitem>
<para>
<xref linkend="server-programming"/> contains information for
advanced users about the extensibility capabilities of the
server. Topics include user-defined data types and
functions.
</para>
</listitem>
<listitem>
<para>
<xref linkend="reference"/> contains reference information about
SQL commands, client and server programs. This part supports
the other parts with structured information sorted by command or
program.
</para>
</listitem>
<listitem>
<para>
<xref linkend="internals"/> contains assorted information that might be of
use to <productname>PostgreSQL</productname> developers.
</para>
</listitem>
</itemizedlist>
</para>
<sect1 id="intro-whatis">
<title> What Is <productname>PostgreSQL</productname>?</title>
<para>
<productname>PostgreSQL</productname> is an object-relational
database management system (<acronym>ORDBMS</acronym>) based on
<ulink url="https://dsf.berkeley.edu/postgres.html">
<productname>POSTGRES, Version 4.2</productname></ulink>,
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.
</para>
<para>
<productname>PostgreSQL</productname> is an open-source descendant
of this original Berkeley code. It supports a large part of the SQL
standard and offers many modern features:
<itemizedlist spacing="compact">
<listitem>
<simpara>complex queries</simpara>
</listitem>
<listitem>
<simpara>foreign keys</simpara>
</listitem>
<listitem>
<simpara>triggers</simpara>
</listitem>
<listitem>
<simpara>updatable views</simpara>
</listitem>
<listitem>
<simpara>transactional integrity</simpara>
</listitem>
<listitem>
<simpara>multiversion concurrency control</simpara>
</listitem>
</itemizedlist>
Also, <productname>PostgreSQL</productname> can be extended by the
user in many ways, for example by adding new
<itemizedlist spacing="compact">
<listitem>
<simpara>data types</simpara>
</listitem>
<listitem>
<simpara>functions</simpara>
</listitem>
<listitem>
<simpara>operators</simpara>
</listitem>
<listitem>
<simpara>aggregate functions</simpara>
</listitem>
<listitem>
<simpara>index methods</simpara>
</listitem>
<listitem>
<simpara>procedural languages</simpara>
</listitem>
</itemizedlist>
</para>
<para>
And because of the liberal license,
<productname>PostgreSQL</productname> can be used, modified, and
distributed by anyone free of charge for any purpose, be it
private, commercial, or academic.
</para>
</sect1>
&history;
¬ation;
&info;
&problems;
</preface>
|
