Author: wyoung
Date: Thu Jun 28 07:26:53 2007
New Revision: 1631
URL: http://svn.gna.org/viewcvs/mysqlpp?rev=1631&view=rev
Log:
Added for_each() section to userman's tutorial chapter
Modified:
trunk/doc/userman/Makefile
trunk/doc/userman/userman.dbx
Modified: trunk/doc/userman/Makefile
URL:
http://svn.gna.org/viewcvs/mysqlpp/trunk/doc/userman/Makefile?rev=1631&r1=1630&r2=1631&view=diff
==============================================================================
--- trunk/doc/userman/Makefile (original)
+++ trunk/doc/userman/Makefile Thu Jun 28 07:26:53 2007
@@ -18,9 +18,9 @@
FO_SS=fo.xsl
HTML_SS=html.xsl
EX_TXT=cgi_jpeg.txt custom1.txt custom2.txt custom3.txt custom4.txt \
- custom5.txt custom6.txt fieldinf1.txt load_jpeg.txt \
+ custom5.txt custom6.txt fieldinf1.txt for_each.txt
load_jpeg.txt \
resetdb.txt simple1.txt simple2.txt simple3.txt stock.txt \
- tquery.txt xaction.txt
+ store_if.txt tquery.txt xaction.txt
## ------------------------
Modified: trunk/doc/userman/userman.dbx
URL:
http://svn.gna.org/viewcvs/mysqlpp/trunk/doc/userman/userman.dbx?rev=1631&r1=1630&r2=1631&view=diff
==============================================================================
--- trunk/doc/userman/userman.dbx (original)
+++ trunk/doc/userman/userman.dbx Thu Jun 28 07:26:53 2007
@@ -840,6 +840,48 @@
instead look at <filename>examples/usequery.cpp</filename>,
which does the same thing as <filename>simple3</filename>,
but with exception-awareness.</para>
+ </sect2>
+
+
+ <sect2>
+ <title>Executing Code for Each Row In a Result Set</title>
+
+ <para>SQL is more than just a database query language. Modern
+ database engines can actually do some calculations on the data
+ on the server side. But, this isn't always the best way to
+ get something done. When you need to mix code and a query,
+ MySQL++'s new <methodname>Query::for_each()</methodname>
+ facility might be just what you need. This is
+ <filename>examples/for_each.cpp</filename>:</para>
+
+ <programlisting><xi:include href="for_each.txt" parse="text"
+ xmlns:xi="http://www.w3.org/2001/XInclude"/></programlisting>
+
+ <para>You only need to read the
+ <function>main()</function> function to get a
+ good idea of what the program does. The key line
+ of code passes an SSQLS examplar and a functor
+ to <methodname>Query::for_each()</methodname>.
+ <methodname>for_each()</methodname> uses the SSQLS
+ instance to build a <computeroutput>select
+ * from TABLE</computeroutput> query,
+ <computeroutput>stock</computeroutput> in this
+ case. It runs that query internally, calling
+ <classname>gather_stock_stats</classname> on each
+ row. This is a pretty contrived example; you could
+ actually do this in SQL, but we're trying to prevent
+ the complexity of the code from getting in the way
+ of the demonstration here.</para>
+
+ <para>If you need a more complex query than the
+ one <methodname>for_each()</methodname> knows
+ how to build, there are two overloads that let
+ you use your own query string. One just takes a
+ functor and uses the query string held within the
+ <classname>Query</classname> object, which you probably
+ built up using <classname>Query</classname>'s stream
+ interface. The other overload just takes the query
+ string directly, along with the functor.</para>
</sect2>
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