Sophie: postgresql-docs-7.3.2-5mdk ppc

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>The Rule System</TITLE
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>PostgreSQL 7.3.2 Documentation</TH
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><H1
><A
NAME="RULES"
>Chapter 13. The Rule System</A
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><DL
><DT
><B
>Table of Contents</B
></DT
><DT
>13.1. <A
HREF="rules.html#RULES-INTRO"
>Introduction</A
></DT
><DT
>13.2. <A
HREF="querytree.html"
>What is a Query Tree?</A
></DT
><DT
>13.3. <A
HREF="rules-views.html"
>Views and the Rule System</A
></DT
><DD
><DL
><DT
>13.3.1. <A
HREF="rules-views.html#AEN32732"
>Implementation of Views in <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
></A
></DT
><DT
>13.3.2. <A
HREF="rules-views.html#AEN32741"
>How SELECT Rules Work</A
></DT
><DT
>13.3.3. <A
HREF="rules-views.html#AEN32789"
>View Rules in Non-SELECT Statements</A
></DT
><DT
>13.3.4. <A
HREF="rules-views.html#AEN32816"
>The Power of Views in <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
></A
></DT
><DT
>13.3.5. <A
HREF="rules-views.html#RULES-VIEWS-UPDATE"
>What about updating a view?</A
></DT
></DL
></DD
><DT
>13.4. <A
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>Rules on INSERT, UPDATE and DELETE</A
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><DD
><DL
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>13.4.1. <A
HREF="rules-insert.html#AEN32833"
>Differences from View Rules</A
></DT
><DT
>13.4.2. <A
HREF="rules-insert.html#AEN32847"
>How These Rules Work</A
></DT
><DT
>13.4.3. <A
HREF="rules-insert.html#AEN32922"
>Cooperation with Views</A
></DT
></DL
></DD
><DT
>13.5. <A
HREF="rules-permissions.html"
>Rules and Permissions</A
></DT
><DT
>13.6. <A
HREF="rules-status.html"
>Rules and Command Status</A
></DT
><DT
>13.7. <A
HREF="rules-triggers.html"
>Rules versus Triggers</A
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><BLOCKQUOTE
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><P
><B
>Author: </B
>     Written by Jan Wieck.  Updates for 7.1 by Tom Lane.
    </P
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></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="RULES-INTRO"
>13.1. Introduction</A
></H1
><P
>     Production rule systems are conceptually simple, but
     there are many subtle points involved in actually using
     them. Some of these points and
     the theoretical foundations of the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
     rule system can be found in
<A
HREF="biblio.html#STON90B"
><I
><A
HREF="http://s2k-ftp.CS.Berkeley.EDU:8000/postgres/papers/ERL-M90-36.pdf"
TARGET="_top"
>On Rules, Procedures, Caching and Views in Database Systems</A
></I
></A
>.</P
><P
>     Some other database systems define active database rules. These
     are usually stored procedures and triggers and are implemented
     in <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> as functions and triggers.</P
><P
>     The query rewrite rule system (the <I
CLASS="FIRSTTERM"
>rule system</I
> from now on) 
     is totally different from stored procedures and triggers.
     It modifies  queries  to
     take rules into consideration, and then passes the modified 
     query to the query planner for planning and execution.   It
     is  very powerful, and can be used for many things such
     as query language procedures, views, and versions.  The
     power  of  this  rule system is discussed in 
<A
HREF="biblio.html#ONG90"
><I
>A Unified Framework for Version Modeling Using Production Rules in a Database System</I
></A
>
 as well as
<A
HREF="biblio.html#STON90B"
><I
><A
HREF="http://s2k-ftp.CS.Berkeley.EDU:8000/postgres/papers/ERL-M90-36.pdf"
TARGET="_top"
>On Rules, Procedures, Caching and Views in Database Systems</A
></I
></A
>.</P
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