mirror of https://github.com/postgres/postgres
Use question marks rather than brackets to delimit optional elements in Tcl synopses. Fix stylesheet misfeature leading to excessively long cross-reference text when linking to a different "part". Remove <body> attributes -- CSS stylesheets should handle that. Improve bibliography formatting. Add fast-forward links for more convenient navigation.REL7_4_STABLE
Peter Eisentraut
22 years ago
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$Header: /cvsroot/pgsql/doc/src/sgml/intro.sgml,v 1.20 2002/10/24 17:48:54 petere Exp $ |
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$Header: /cvsroot/pgsql/doc/src/sgml/intro.sgml,v 1.21 2003/09/08 23:02:28 petere Exp $ |
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--> |
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|
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<sect1 id="intro-whatis"> |
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<title> What is <productname>PostgreSQL</productname>?</title> |
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|
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<para> |
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<productname>PostgreSQL</productname> is an object-relational |
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database management system (<acronym>ORDBMS</acronym>) based on |
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<ulink url="http://s2k-ftp.CS.Berkeley.EDU:8000/postgres/postgres.html"> |
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<productname>POSTGRES, Version 4.2</productname></ulink>, |
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developed at the University of California at Berkeley Computer |
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Science Department. The <productname>POSTGRES</productname> |
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project, led by Professor Michael Stonebraker, was sponsored by |
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the Defense Advanced Research Projects Agency |
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(<acronym>DARPA</acronym>), the Army Research Office |
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(<acronym>ARO</acronym>), the National Science Foundation |
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(<acronym>NSF</acronym>), and ESL, Inc. |
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</para> |
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|
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<para> |
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<productname>PostgreSQL</productname> is an open-source descendant of |
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this original Berkeley code. It provides SQL92/SQL99 language support |
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and other modern features. |
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</para> |
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|
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<para> |
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<productname>POSTGRES</productname> pioneered many of the |
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object-relational concepts now becoming available in some commercial |
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databases. |
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Traditional relational database management systems |
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(<acronym>RDBMS</acronym>) support a data model consisting of a collection |
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of named relations, containing attributes of a specific |
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type. In current commercial systems, possible types |
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include floating point numbers, integers, character |
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strings, money, and dates. It is commonly recognized |
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that this model is inadequate for future data-processing applications. |
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The relational model successfully replaced previous |
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models in part because of its <quote>Spartan simplicity</quote>. |
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However, this simplicity makes the |
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implementation of certain applications very difficult. |
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<productname>PostgreSQL</productname> offers substantial additional |
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power by incorporating the following additional |
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concepts in such a way that users can easily |
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extend the system: |
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|
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<itemizedlist spacing="compact"> |
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<listitem> |
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<simpara>inheritance</> |
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</listitem> |
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<listitem> |
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<simpara>data types</> |
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</listitem> |
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<listitem> |
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<simpara>functions</simpara> |
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</listitem> |
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</itemizedlist> |
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</para> |
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|
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<para> |
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Other features provide additional power and flexibility: |
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|
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<itemizedlist spacing="compact"> |
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<listitem> |
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<simpara>constraints</simpara> |
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</listitem> |
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<listitem> |
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<simpara>triggers</simpara> |
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</listitem> |
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<listitem> |
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<simpara>rules</simpara> |
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</listitem> |
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<listitem> |
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<simpara>transactional integrity</simpara> |
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</listitem> |
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</itemizedlist> |
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</para> |
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|
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<para> |
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These features put <productname>PostgreSQL</productname> into the |
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category of databases referred to as |
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<firstterm>object-relational</firstterm>. Note that this is distinct |
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from those referred to as <firstterm>object-oriented</firstterm>, |
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which in general are not as well suited to supporting |
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traditional relational database languages. |
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So, although <productname>PostgreSQL</productname> has some |
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object-oriented features, it is firmly in the relational database |
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world. In fact, some commercial databases have recently |
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incorporated features pioneered by <productname>PostgreSQL</productname>. |
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</para> |
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|
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</sect1> |
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|
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<!-- Keep this comment at the end of the file |
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Local variables: |
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mode:sgml |
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sgml-omittag:nil |
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sgml-shorttag:t |
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sgml-minimize-attributes:nil |
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sgml-always-quote-attributes:t |
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sgml-indent-step:1 |
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sgml-indent-data:t |
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sgml-parent-document:nil |
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sgml-default-dtd-file:"./reference.ced" |
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sgml-exposed-tags:nil |
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sgml-local-catalogs:("/usr/lib/sgml/catalog") |
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sgml-local-ecat-files:nil |
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End: |
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--> |
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<preface id="preface"> |
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<title>Preface</title> |
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|
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<para> |
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This book is the official documentation of PostgreSQL. It is being |
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written by the PostgreSQL developers and other volunteers in |
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parallel to the development of the PostgreSQL software. It |
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describes all the functionality that the current version of |
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PostgreSQL officially supports. |
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</para> |
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|
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<para> |
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To make the large amount of information about PostgreSQL manageable, |
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this book has been organized in several parts. Each part is |
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targeted at a different class of users, or at users in different |
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stages of their PostgreSQL experience: |
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|
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<itemizedlist> |
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<listitem> |
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<para> |
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<xref linkend="tutorial"> is an informal introduction for new users. |
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</para> |
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</listitem> |
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|
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<listitem> |
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<para> |
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<xref linkend="sql"> documents the <acronym>SQL</acronym> query |
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language environment, including data types and functions, as well |
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as user-level performance tuning. Every |
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<productname>PostgreSQL</> user should read this. |
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</para> |
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</listitem> |
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|
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<listitem> |
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<para> |
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<xref linkend="admin"> describes the installation and |
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administration of the server. Everyone that runs a PostgreSQL |
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server, be it for private use or for others, should read this |
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part. |
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</para> |
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</listitem> |
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|
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<listitem> |
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<para> |
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<xref linkend="client-interfaces"> describes the programming |
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interfaces for PostgreSQL client programs. |
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</para> |
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</listitem> |
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|
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|
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<listitem> |
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<para> |
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<xref linkend="server-programming"> contains information for |
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advanced users about the extensibility capabilities of the |
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server. Topics are, for instance, user-defined data types and |
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functions. |
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</para> |
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</listitem> |
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|
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<listitem> |
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<para> |
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<xref linkend="reference"> contains information about the syntax |
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of SQL commands, client and server programs. This part supports |
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the other parts with structured information sorted by command or |
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program. |
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</para> |
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</listitem> |
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</itemizedlist> |
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</para> |
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|
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<sect1 id="intro-whatis"> |
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<title> What is <productname>PostgreSQL</productname>?</title> |
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|
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<para> |
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<productname>PostgreSQL</productname> is an object-relational |
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database management system (<acronym>ORDBMS</acronym>) based on |
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<ulink url="http://s2k-ftp.CS.Berkeley.EDU:8000/postgres/postgres.html"> |
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<productname>POSTGRES, Version 4.2</productname></ulink>, developed |
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at the University of California at Berkeley Computer Science |
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Department. POSTGRES pioneered many concepts that only became |
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available in some commercial database systems much later. |
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</para> |
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|
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<para> |
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<productname>PostgreSQL</productname> is an open-source descendant |
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of this original Berkeley code. It supports SQL92 and SQL99 and |
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offers many modern features: |
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|
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<itemizedlist spacing="compact"> |
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<listitem> |
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<simpara>complex queries</simpara> |
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</listitem> |
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<listitem> |
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<simpara>foreign keys</simpara> |
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</listitem> |
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<listitem> |
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<simpara>triggers</simpara> |
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</listitem> |
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<listitem> |
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<simpara>views</simpara> |
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</listitem> |
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<listitem> |
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<simpara>transactional integrity</simpara> |
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</listitem> |
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<listitem> |
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<simpara>multiversion concurrency control</simpara> |
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</listitem> |
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</itemizedlist> |
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|
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Also, PostgreSQL can be extended by the user in many ways, for |
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example by adding new |
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|
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<itemizedlist spacing="compact"> |
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<listitem> |
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<simpara>data types</simpara> |
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</listitem> |
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<listitem> |
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<simpara>functions</simpara> |
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</listitem> |
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<listitem> |
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<simpara>operators</simpara> |
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</listitem> |
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<listitem> |
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<simpara>aggregate functions</simpara> |
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</listitem> |
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<listitem> |
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<simpara>index methods</simpara> |
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</listitem> |
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<listitem> |
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<simpara>procedural languages</simpara> |
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</listitem> |
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</itemizedlist> |
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</para> |
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<para> |
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And because of the liberal license, PostgreSQL can be used, |
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modified, and distributed by everyone free of charge for any |
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purpose, be it private, commercial, or academic. |
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</para> |
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</sect1> |
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|
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&history; |
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¬ation; |
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&info; |
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&problems; |
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|
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</preface> |
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|
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