New User-Defined Function Syntax in SQL::Statement

[Jeff Zucker]

[Copied to dbi-dev, but please reply to dbi-users]
Since the cat is out of the bag on upcoming SQL::Statement changes, 
here's a preview.  Comments on the proposed syntax will be much appreciated.

The major additions will be column name aliases (thanks Robert 
Rothenberg), improved parsing (thanks Dean Arnold), and expanded support 
for functions including support for user-defined functions.   Here's the 
syntax I am thinking of, please comment.

$dbh->do("CREATE FUNCTION foo");
   # pre-declares function foo, a perl subroutine in current package
$dbh->do("CREATE FUNCTION foo AS Bar::baz");
   # pre-declares function foo, using baz, a subroutine in package Bar
$dbh->do("LOAD Qux::Quimble");
   # pre-declares all functions in package Qux::Quimble named 
SQL_FUNCTION_x
     where x is all upper case letters or underscore

$dbh->do("DROP FUNCTION foo")
   # unloads a function - e.g. if you want the parser to fail when it finds
     a function not supported by your dialect
Functions, once loaded can be used almost anywhere that a value, column, 
or table can be used in SQL (assuming that the function returns the 
appropriate values(s) for its context).  This means that functions can 
work as sub queries, predicates and procedures in addition to working as 
functions.

$sth = $dbh->prepare("SELECT MyFunc(args)");
$sth = $dbh->prepare("SELECT * FROM MyFunc(args) WHERE ...");
$sth = $dbh->prepare("SELECT * FROM TableZ WHERE MyFunc(args) AND ...");
$sth = $dbh->prepare("SELECT * FROM TableZ WHERE colX < MyFunc(args) AND 
...");

--
Jeff