Containable won't filter 2nd level model with HABTM & hasMany

Question

What I have:

"A" HABTM "C" HABTM "A" through join table "B"
"A" hasMany "B" belongsTo "A"
"C" is ordered by a "B" field

What I want:

// result:
[0] => array( 
    A => array( /* single model's fields I still need*/ ),
    C => array(
        [0] => array( C.field1, C.field2, ... /* Model C fields*/ ), 
        [1] => array( C.field1, C.field2, ... )
    )
) 

What I've tried:

// this gives me data I don't need:
A->find('all', array( 'conditions' => array( 'id' => $id ) ) )
// result:
[0] => array( 
    A => array( /* single model's fields I need*/ ),
    B => array( /* I DON'T NEED */
        [0] => array( ... )
        [1] => array( /* ... etc, tons records I don't need */ )
    ),
    C => array(
        [0] => array( C.field1, C.field2, ... /* I need these fields*/ 
            [B] => array( /* I DON'T NEED */ )
        ),
        [1] => array( C.field1, C.field2, ...  )
            [B] => array( /* ... etc, each has a model B I don't need ... */)
        )
    )
)

Using Containable, I can cut down the query quite a bit, but there's still associated model cruft:

// this is a little better
A->find('all', array( 
    'conditions' => array( 'id' => $id ),
    'contain' => array( 'C' )
))
// result:
[0] => array( 
    A => array( /* single model's fields I still need*/ ),
    C => array(
        [0] => array( C.field1, C.field2, ... /* I still need Model C fields*/ 
            [B] => array( /* I still DON'T need this Model's fields */ )
        ),
        [1] => array( C.field1, C.field2, ... 
            [B] => array( /* ... still has unneeded model B */)
        )
    )
)

NB1: I've read this, this, and this from the book, as well as this and this.

NB2: I've also tried

C->recursive = -1 // no effect

C->unbindModel(array('hasAndBelongsToMany'=>A)) // no effect

A->find('all', array(                    // not what I want, but it's still 
    'conditions' => array('id' => $id),  // odd that this doesn't filter C's 
    'contain' => array('A.B')));         // fields out. same as second result

A->find('all', array(                    // also not what I want, but it's 
    'conditions' => array('id' => $id),  // weird that this doesn't filter B's 
    'contain' => array('A.B.field')));   // fields at all; 

Answer 1

The ContainableBehavior will automatically return fields that are required to map results.

Quoting from a page that you already read:

$this->Post->find('all', array('contain' => 'Comment.author'));

... // data returned:

[Comment] => Array
    (
        [0] => Array
            (
                [author] => Daniel
                [post_id] => 1
            )
...

As you can see, the Comment arrays only contain the author field (plus the post_id which is needed by CakePHP to map the results).

In the case of HABTM relationships, the join model with the associated foreign keys is returned, since the a_id and c_id fields are required by Containable. My suggestion is to just ignore it and take the values you need. If you want, you could probably take a look at joins because Containable sometimes queries the DB many, many times. However, the data for associated models won't be returned as nicely as Containable.