Hello,

How can I display and allow editing of $many_many_extraFields when using a control like the ManyManyComplexTableField?

Background
When doing a many-to-many relationship, SilverStripe allows data to be stored in the junction table. This is set up using DataObject's static many_many_extraFields property.

The specific problem I'm trying to solve involves Quotes which may be related to any number of Qualities. Some of these relationships should be marked as primary. I've tried to do this using

	public static $many_many_extraFields = array(
		'Qualities' => array('Primary' => 'Boolean')
	);

but would like the CMS admin user to have a way to edit this property.

Any ideas?

Sincerely,
Ben

I'm wondering if this is an uncommon thing to do in SS. I'm curious...how many of you out there have used $many_many_extraFields?

AFAIK, there are currently no CRUD interfaces for many-to-many extra fields.

At the moment there's a way to add the extra data by setting the second parameter to the add() method when you're manipulating the relationship. Here's an example of adding a Member to a Group.

$member = new Member();
$group = DataObject::get_one('Group', "Code = 'forum-members'");

$group->Members()->add($member, array(
	'Position' => 'Player'
));

There's also a way to inspect which extra fields are available for a relation using the method many_many_extraFields($component) (found on DataObject) where $component is the relationship name that you want the extra fields spec for.

Unfortunately, in the end you'll have to do your own code to add or edit extra fields columns on the junction table.

There is a plan to rework ComplexTableField so that it works in a more robust way, this would most likely include scaffolding the extra fields if you're editing a many-to-many relationship.

Sean

Thanks for this info, Sean.

Is it still the case that there is no CRUD interface for many_many_extraFields?

What Sean remarked allows to modify, add and remove rows from the join table, which was enough for me.

$cs = $group->getManyManyComponents('Member'); // returns ComponentSet
$cs->add($otherObj, array('FieldOnJoinTable'=>1)); // adds a row
$cs->add($otherObj, array('FieldOnJoinTable'=>2)); // modifies a row
$cs->remove($otherObj);

When comes to querying though, this is a bit tricky, you need to use $join parameters of DataObject, or other getters. There are also other methods on ComponentSet like removeAll, setByIDList and so on, have a look at the ComponentSet. What else do you need?

m.

I would be interested in a CRUD interface for extra fields.

I want to define a many-many relation with three additional fields: one enumeration and two HTMLtext fields. Is there an easy way to enable these to be edited through the admin interface?

Yeah, this would be great. Any progress on this?

I actually want to use the data in the many_many_extraFields, not just filter my results based on it. This means that using a regular old $join on the DataObject won't work, since it doesn't actually join the tables. Had to resort to the old SQLQuery object. Am I missing something?