Sophie

Sophie

distrib > Mandriva > 2010.0 > i586 > media > contrib-release > by-pkgid > 415a9558429d583fc9b2617edd1d24a6 > files > 891

postgresql8.3-docs-8.3.8-1mdv2010.0.i586.rpm

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>Views</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 8.3.8 Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="Advanced Features"
HREF="tutorial-advanced.html"><LINK
REL="PREVIOUS"
TITLE="Introduction"
HREF="tutorial-advanced-intro.html"><LINK
REL="NEXT"
TITLE="Foreign Keys"
HREF="tutorial-fk.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="2009-09-04T05:13:45"></HEAD
><BODY
CLASS="SECT1"
><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 8.3.8 Documentation</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="tutorial-advanced-intro.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="tutorial-advanced.html"
>Fast Backward</A
></TD
><TD
WIDTH="60%"
ALIGN="center"
VALIGN="bottom"
>Chapter 3. Advanced Features</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="top"
><A
HREF="tutorial-advanced.html"
>Fast Forward</A
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="top"
><A
HREF="tutorial-fk.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="TUTORIAL-VIEWS"
>3.2. Views</A
></H1
><A
NAME="AEN933"
></A
><P
>    Refer back to the queries in <A
HREF="tutorial-join.html"
>Section 2.6</A
>.
    Suppose the combined listing of weather records and city location
    is of particular interest to your application, but you do not want
    to type the query each time you need it.  You can create a
    <I
CLASS="FIRSTTERM"
>view</I
> over the query, which gives a name to
    the query that you can refer to like an ordinary table:

</P><PRE
CLASS="PROGRAMLISTING"
>CREATE VIEW myview AS
    SELECT city, temp_lo, temp_hi, prcp, date, location
        FROM weather, cities
        WHERE city = name;

SELECT * FROM myview;</PRE
><P>
   </P
><P
>    Making liberal use of views is a key aspect of good SQL database
    design.  Views allow you to encapsulate the details of the
    structure of your tables, which might change as your application
    evolves, behind consistent interfaces.
   </P
><P
>    Views can be used in almost any place a real table can be used.
    Building views upon other views is not uncommon.
   </P
></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="tutorial-advanced-intro.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="tutorial-fk.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Introduction</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="tutorial-advanced.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Foreign Keys</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>