use DBI;
my $database = 'databasename';
my $dbuser = 'username';
my $usrpsswd = 'password';
my $dbtable = 'tablename';

##</code><code>##

my $dbconnection = DBI->connect("dbi:Pg:dbname=$database", $dbuser, $usrpsswd);

##</code><code>##

my $query = $dbconnection->prepare(<<End_SQL);
SELECT something1,something2 FROM $dbtable
End_SQL

##</code><code>##

$query->execute();

##</code><code>##

while (($something1,$something2) = $query->fetchrow_array() )    {
     do your stuff here
     }
# and then disconnect
$dbconnection->disconnect();