doc/src/sgml/intro.sgml

   1 <!-- doc/src/sgml/intro.sgml -->
   2
   3 <preface id="preface">
   4  <title>Preface</title>
   5
   6  <para>
   7   This book is the official documentation of
   8   <productname>PostgreSQL</productname>.  It has been written by the
   9   <productname>PostgreSQL</productname> developers and other
  10   volunteers in parallel to the development of the
  11   <productname>PostgreSQL</productname> software.  It describes all
  12   the functionality that the current version of
  13   <productname>PostgreSQL</productname> officially supports.
  14  </para>
  15
  16  <para>
  17   To make the large amount of information about
  18   <productname>PostgreSQL</productname> manageable, this book has been
  19   organized in several parts.  Each part is targeted at a different
  20   class of users, or at users in different stages of their
  21   <productname>PostgreSQL</productname> experience:
  22
  23   <itemizedlist>
  24    <listitem>
  25     <para>
  26      <xref linkend="tutorial"/> is an informal introduction for new users.
  27     </para>
  28    </listitem>
  29
  30    <listitem>
  31     <para>
  32      <xref linkend="sql"/> documents the <acronym>SQL</acronym> query
  33      language environment, including data types and functions, as well
  34      as user-level performance tuning.  Every
  35      <productname>PostgreSQL</productname> user should read this.
  36     </para>
  37    </listitem>
  38
  39    <listitem>
  40     <para>
  41      <xref linkend="admin"/> describes the installation and
  42      administration of the server.  Everyone who runs a
  43      <productname>PostgreSQL</productname> server, be it for private
  44      use or for others, should read this part.
  45     </para>
  46    </listitem>
  47
  48    <listitem>
  49     <para>
  50      <xref linkend="client-interfaces"/> describes the programming
  51      interfaces for <productname>PostgreSQL</productname> client
  52      programs.
  53     </para>
  54    </listitem>
  55
  56
  57    <listitem>
  58     <para>
  59      <xref linkend="server-programming"/> contains information for
  60      advanced users about the extensibility capabilities of the
  61      server.  Topics include user-defined data types and
  62      functions.
  63     </para>
  64    </listitem>
  65
  66    <listitem>
  67     <para>
  68      <xref linkend="reference"/> contains reference information about
  69      SQL commands, client and server programs.  This part supports
  70      the other parts with structured information sorted by command or
  71      program.
  72     </para>
  73    </listitem>
  74
  75    <listitem>
  76     <para>
  77      <xref linkend="internals"/> contains assorted information that might be of
  78      use to <productname>PostgreSQL</productname> developers.
  79     </para>
  80    </listitem>
  81   </itemizedlist>
  82  </para>
  83
  84  <sect1 id="intro-whatis">
  85   <title> What Is <productname>PostgreSQL</productname>?</title>
  86
  87   <para>
  88    <productname>PostgreSQL</productname> is an object-relational
  89    database management system (<acronym>ORDBMS</acronym>) based on
  90    <ulink url="https://dsf.berkeley.edu/postgres.html">
  91    <productname>POSTGRES, Version 4.2</productname></ulink>,
  92    developed at the University of California at Berkeley Computer Science
  93    Department.  POSTGRES pioneered many concepts that only became
  94    available in some commercial database systems much later.
  95   </para>
  96
  97   <para>
  98    <productname>PostgreSQL</productname> is an open-source descendant
  99    of this original Berkeley code.  It supports a large part of the SQL
 100    standard and offers many modern features:
 101
 102    <itemizedlist spacing="compact">
 103     <listitem>
 104      <simpara><link linkend="sql">complex queries</link></simpara>
 105     </listitem>
 106     <listitem>
 107      <simpara><link linkend="ddl-constraints-fk">foreign keys</link></simpara>
 108     </listitem>
 109     <listitem>
 110      <simpara><link linkend="triggers">triggers</link></simpara>
 111     </listitem>
 112     <listitem>
 113      <simpara><link linkend="sql-createview-updatable-views">updatable views</link></simpara>
 114     </listitem>
 115     <listitem>
 116      <simpara><link linkend="transaction-iso">transactional integrity</link></simpara>
 117     </listitem>
 118     <listitem>
 119      <simpara><link linkend="mvcc">multiversion concurrency control</link></simpara>
 120     </listitem>
 121    </itemizedlist>
 122
 123    Also, <productname>PostgreSQL</productname> can be extended by the
 124    user in many ways, for example by adding new
 125
 126    <itemizedlist spacing="compact">
 127     <listitem>
 128      <simpara><link linkend="datatype">data types</link></simpara>
 129     </listitem>
 130     <listitem>
 131      <simpara><link linkend="functions">functions</link></simpara>
 132     </listitem>
 133     <listitem>
 134      <simpara><link linkend="functions">operators</link></simpara>
 135     </listitem>
 136     <listitem>
 137      <simpara><link linkend="functions-aggregate">aggregate functions</link></simpara>
 138     </listitem>
 139     <listitem>
 140      <simpara><link linkend="indexes">index methods</link></simpara>
 141     </listitem>
 142     <listitem>
 143      <simpara><link linkend="server-programming">procedural languages</link></simpara>
 144     </listitem>
 145    </itemizedlist>
 146   </para>
 147
 148   <para>
 149    And because of the liberal license,
 150    <productname>PostgreSQL</productname> can be used, modified, and
 151    distributed by anyone free of charge for any purpose, be it
 152    private, commercial, or academic.
 153   </para>
 154  </sect1>
 155
 156  &history;
 157  &notation;
 158  &info;
 159  &problems;
 160
 161 </preface>