my $sth = $dbh->prepare("insert into t (foo,bar) values (?,?)");
$sth->execute("foo", 1);
$sth->execute("bar", 2);
$sth->execute("baz", 3);

##</code><code>##

while (my $record = $sth->fetchrow_hashref) {

  # Manipulate record as needed
  $record->{'foo'} = &bar( $record->{'baz'} );

  push @records, $record;
}