Relations between tables in CakePHP

Question

I need help with creating the right relations between 3 tables in CakePHP. These are:

1. users - pK = user_id
2. books - pK = book_id
3. books_users

I am trying to make my users_books-table contain all the relations between what book belongs to what user, and vica versa, like:

ID  |  user_id  |  book_id
--------------------------
 1      321          231
 2      24           58
 3      80           58
 4      24           75
 5      80           231

My approach has been to make a hasAndBelongsToMany-relation, but when adding a new book the users_books-table does not get populated with any info.

In my controller I've tried the saveAll() and saveAssociated()-method but nothing works.

Can anybody help me with what association-code i should put in my Models to make this work?

public function addBook() {
    $this->Book->create();

    $this->request->data['Book']['book_user_id'] = $this->Auth->user('user_id');
    $data = $this->request->data['Book'];

    if (!$data['book_img']['name']) {
        unset($data['book_img']);
    }

    if ($this->Book->saveAll($data)) {
        $this->Session->setFlash(__('The book has been saved.'));
        return $this->redirect(array('action' => 'index'));
    } else {
        $this->Session->setFlash(__('The book could not be saved. Please, try again.'));
    }
}

The the new array:

$test = array('User' => $this->Auth->user('user_id'), 'Book' => $data);
pr($test);

Outputs this:

Array
(
[User] => 4
[Book] => Array
    (
        [book_study_id] => ha_fil
        [book_title] => The title
        [book_price] => 123
        [book_isbn] => 123
        [book_user_id] => 4
    )

)

Thanks in advance, Jesper.

Answer 1

You are quite confused with HABTM...

Please refer to the docs when you are in doubt.

In there you have an example of how the saved array should be

Array
(
    [Recipe] => Array
        (
            [id] => 42
        )
    [Tag] => Array
        (
            [name] => Italian
        )
)

So, transforming that to what you want to do, you need to save this array...

Array
(
    [User] => Array
        (
            [id] => $this->Auth->user('user_id')
        )
    [Book] => Array
        (
            [name] => book,
            /* your other book stuff */
        )
)

and do a simple $this->save($suggestedBySOArray) to save the relation.

The link to the docs have more examples on how to save data to HABTM if you need more examples.

EDIT:

I'll add a bit more code to help you get on the right path. Now, I'm assuming things* in this example since your question doesn't say:
1) you are creating a new book, not updating a relation between an existing user with and existing book.
2) you are just adding one book, not many

$this->Book->create();

 //what did you intent to do with this piece of code btw? you don't have a "book_user_id" column anywhere
//$this->request->data['Book']['book_user_id'] = $this->Auth->user('user_id');

$data = $this->request->data;

if (!$data['Book']['book_img']['name']) {
    unset($data['Book']['book_img']);
}

$data['User']['id'] = $this->Auth->user('user_id');

if ($this->Book->save($data)) {
    $this->Session->setFlash(__('The book has been saved.'));
    return $this->redirect(array('action' => 'index'));
} else {
    $this->Session->setFlash(__('The book could not be saved. Please, try again.'));
}

That ought to do it.

Now, please, read the docs for anything further, it's got examples and everything.

Also, if what @Anilkumar suspected what correct ("You're trying to add book for only one user"), go with hasMany instead of HABTM.