Re: Algebraic data retrieval with DBIx::Array

[Juerd]

Sigh. I had overlooked this post before but I do feel that it needs a reply to set a few things straight for other people who might stumble upon this thread.

But what good is cleaner code if you end up with circular references when you try to use DBIx::Simple in a simple has-a relationship?

The thing you complained about wasn't a has-a relationship, but a method that creates and returns a DBIx::Simple object, called in a chain. As you've previously demonstrated, this causes premature destruction. (One of the possible work-arounds is "don't do that, then", i.e. don't chain.) Even then, the way you used DBIx::Simple doesn't cause a circular reference. DBIx::Simple specifically avoids creating circular references; the "fix" that you suggested, however, would have created circular references. That's one reason that your suggested change was rejected.

A has-a works perfectly with DBIx::Simple and Moose. It does mean that the D::S object will remain in use as long as your Moose object is, but that's what has-a's are for, of course... :)

package Argh;

use Moose;
use DBIx::Simple;

has 'db' => (
    is      => 'rw',
    isa     => 'DBIx::Simple',
    lazy    => 1,
    default => sub { DBIx::Simple->connect("dbi:SQLite::memory:") },
);

sub meh {
    my ($self) = @_;

    my $db = $self->db;
    say $db->query("SELECT 2 - 1")->list;

    say $self->db->query("SELECT 1 + 1")->list;
}

1;