$sql = qq{select course_id,course_name,course_sitting_id,course_sitting_date from courses};
$sth = $dbh->prepare($sql) or die . . .;
$sth->execute() or die  . . . .;
while (@fetch = $sth->fetchrow)
		{ . . . . 	

##</code><code>##

10,Programming 101,1,01-SEP-2011
20,Databases 101,1,03-SEP-2011
10,Programming 101,2,20-SEP-2011
20,Databases 101,2,27-SEP-2011

##</code><code>##

my %courses= (
	'10' => {
		'desc' => 'Programming 101',
		'sittings' => {
			'1' => '01-SEP-2011',
			'2' => '20-SEP-2011',
		},
	},
	'20' => {
		'desc' => 'Databases 101',
		'sittings' => {
			'1' => '03-SEP-2011',
			'2' => '27-SEP-2011',
		},
	},
);