Because the iterator ->fetchrow_hashref returns one scalar undef when done

Usually I use fetchrow_array - I don't think I have used fetchrow_hashref before.

The problem came because I was converting from this code

    my @frames;
    my $query = $dbh->prepare("SELECT idFrame, name, colour FROM Frame
+");
    $query->execute();
    while (my ($id, $name, $colour) = $query->fetchrow_array) {
        my $frame = {
            'image'  => 'test_thumb.jpg',
            'id'     => $id,
            'name'     => $name,
            'colour' => $colour,
        };
        push @frames, $frame;
    }
    my $vars = {
        'frames' => \@frames,
    };
    $template->process("admin_frames.tt", $vars);
[download]

It seemed silly to me to be fetching the elements of an array, using those to build an anonymous hash and adding the reference to it to an array. Why not just fetch the hashref and add that to the array?

    my @frames;
    my $query = $dbh->prepare("SELECT idFrame, name, colour FROM Frame
+");
    $query->execute();
    while (my ($frame) = $query->fetchrow_hashref) {
        $$frame{'image'} = 'test_thumb.jpg';
        push @frames, $frame;
    }
    my $vars = {
        'frames' => \@frames,
    };
    $template->process("admin_frames.tt", $vars);
[download]

Finding the error of my ($frame) = $query->fetchrow_hashref instead of my $frame = $query->fetchrow_hashref took some time. Not helped by developing it on a webserver so when the loop didn't end, I assumed the connection was just being ultra slow!

I suspect that there is a more elegant solution that doesn't involve iterating through the rows from the database using fetchall_hashref but that's (possibly) for another day. There will only ever be a handful of rows returned by this query.