Useless variable when looping channel entries - relationship field

Question

I'm looping through channel entries. When I try to output the value of a relationship field, I seem to be getting some sort of numerical id (it's not the entry id of the current channel or the channel it is related to; I checked). What exactly is that number? How is this number related to the channel it relates to?

Ultimately, I'm trying to change the structure of the data for some other use later on. So, is there anything in the two channels that are identical so that I can connect the two?

UPDATE 1: code snippet

<ul>
    {exp:channel:entries channel="regions" sort="asc" orderby="title" disable="categories|member_data|pagination"}
        <li>{title} - {entry_id}</li>
    {/exp:channel:entries}
</ul>

<?php $formatted_branches = array(); ?>
{exp:channel:entries channel="regions" sort="asc" orderby="title" disable="categories|member_data|pagination"}
    {reverse_related_entries sort="asc" orderby="title" channel="branch"}
        <?php
            $formatted_branches["{participant_status}"]["{region}"]["{parent_company}"][] = array('branch_name' => "{branch_name}");
        ?>
    {/reverse_related_entries}
{/exp:channel:entries}
<?php var_dump($formatted_branches); ?>

Answer 1

The value is a rel_id from the exp_relationships table, which is used as a linking table for all relationships.

Typically you want to use the Relationship tags provided by the Channel Entries loop to work with relationship fields, you should not generally attempt to use them as single variables since they are not generally useful for anything (expect in some special circumstances such as working with custom plugin code).

It looks like you are trying to reference a related entry from inside of a {reverse_related_entries} loop - the same issue applies here, the Relationship field itself only returns the rel_id value - you need to use Channel Entries tag and {related_entries} to turn this into a usable value.

You could do this by using an embed, for instance, which would load the given entry from the {reverse_related_entries} loop, then loop over it's {related_entries} loop:

Main template

{exp:channel:entries channel="regions" sort="asc" orderby="title" disable="categories|member_data|pagination"}
    {reverse_related_entries sort="asc" orderby="title" channel="branch"}
        {embed="pages/branch_block" entry_id="{entry_id}"}
    {/reverse_related_entries}
{/exp:channel:entries}

pages/branch_block embed:

{exp:channel:entries entry_id="{embed:entry_id}" dynamic="off" disable="categories|member_data|pagination"}
    {related_entries sort="asc" orderby="title" channel="branch"}
        {entry_id} - {title}<br/>
    {/related_entries}
{/exp:channel:entries}

However, note that using embeds in this way is typically not recommended since it causes nested database calls. If you have a limited number of entries in this relationship however, it's probably okay.

You may also want to consider using Playa instead of the built in Relationships field. It's template tags may be closer to what you expect.

I should also point out that your use of PHP in this template is probably something you want to avoid. It would be a lot better to do this work in a plugin, then package up the results and return it to the template. PHP should never be turned on in templates. I gave a talk on creating simple plugins and wrote up a blog post about it that you may find interesting.