Using DataMapper ORM and Codeigniter to select join table value in a many to many relationship

Question

I have this table structure:

| users | --- has many > --- | preferences_users | --- < has many --- | preferences |

A preference could be something like "first name" or "surname" but the value for these preferences are stored in the joining table.

I am using Codeigniter and Datamapper ORM to get relational tables into objects, however I am not sure how to get this value in the joining table.

I am doing this:

$user = new User();
$user->where('unique_url', $url)->get();
$user->preferences->get_iterated();

My relationships are set up so that they both have $has_many = array('tablename'); and I am able to get the values from each table.

HOwever I want to be able to get a table column value from the joining table, does anyone know how to do this?

Thanks,

Ian

Answer 1

I found the answer in the documentation:

$object->include_join_fields()

There are no options for this method. Set it right before adding a relationship. You can either use it before a {$query}_related_{$model}, or before calling get() on a related item. All fields on the table that are not part of the relationship are included, and are prepended with "join_".

This method may return unexpected results or throw errors with deep relationships.

Usage:

// Create User $u = new User(); $u->get_by_id($userid);

// get all alarms for this user, and include the extra 'wasfired'
field $u->alarm->include_join_fields()->get();

foreach($u->alarm as $alarm) {
    if($alarm->join_wasfired) {
        echo("{$alarm->name} was fired\n");
    } else {
        echo("{$alarm->name} was NOT fired\n");
    }
}

See Working with Join Fields for more details.

Answer 2

You can use this:

$Object->joinedObject->include_join_fields()->get();

Then to get the join field:

$Object->{join}_count;

Be aware to add join_ before field (count) name as referenced in the documentation.

Thanks.