Item11871: minor doc updates

git-svn-id: http://svn.foswiki.org/trunk/SqlGridPlugin@14885 0b4bb1d4-4e5a-0410-9cc4-b2b747904278

data/System/SqlGridPlugin.txt

@@ -38,15 +38,19 @@ This is a bit messy right now - the interface needs to be changed a bit.
 
 All additional parameters are passed verbatim through to JQGridPlugin.
 
----+++ sql Parsing
+---+++ SQL Parsing
 If you provide an sql parameter, then the plugin will parse it and inject the following parameters.
 If you have an SQL expression that's too complicated for the parser then instead of providing an sql parameter
-you can set the following:
+you can set the following parameters:
 
    * fromwhere_connectorparam - the part of the SQL query after 'from'.  
    * columns - a comma-separated list of columns.
    * col_${col}_expr_connectorparam - for each column, the sql expression for that column.
 
+The parser assumes that the select list expressions contain balanced parentheses.  So this would not work:
+
+=select '(' || foo as bar from table1=
+
 ---++ Examples
 
 %<nop>SQLGRID{<br/>

lib/Foswiki/Plugins/SqlGridPlugin.pm

@@ -70,6 +70,9 @@ sub initPlugin {
     return 1;
 }
 
+# I experimented with caching, however it made no performance difference to my queries.
+# Leaving this code in here for now just in case.
+#
 #use File::Spec;
 #use Storable;
 #

lib/Foswiki/Plugins/SqlGridPlugin/SqlParser.pm

@@ -14,6 +14,8 @@ Parses an SQL expression and returns a hashtable that contains:
    * fromwhere_connectorparam - the part of the SQL query after 'from'.  
    * columns - a comma-separated list of columns.
    * col_${col}_expr_connectorparam - for each column, the sql expression for that column.
+
+Adapted from http://www.perl.com/pub/2006/01/05/parsing.html
 =cut
 
 sub parse {