CakePHP显示HABTM关联

Question

I'm new to CakePHP and just want to display a list of associated tags in a post's view.

I have searched all over the web and nothing seems to work.

This is what I have at the moment:

// PostController
public function view($id = null) {
    $this->set('tags', $this->Post->Tag->find('all', array('conditions' => array('PostTag.post_id' => $id))));

    if (!$id) {
        throw new NotFoundException(__('Invalid post'));
    }

    $post = $this->Post->findById($id);
    if (!$post) {
        throw new NotFoundException(__('Invalid post'));
    }
    $this->set('post', $post);
}

// Post's view.ctp
echo $this->Text->toList($tags);

This is the error I'm getting:

Error: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'PostTag.post_id' in 'where clause'

This should be so easy but I am completely stuck.

Thanks to anyone who can help!

Answer 1

Finally! After finding another question here about joining tables and some experimentation, I got it to work.

public function view($id = null) {
    $options = array(
        'joins' => array(
            array('table' => 'posts_tags',
                'alias' => 'PostTags',
                'type' => 'left',
                'conditions' => array(
                    'Post.id = PostTags.post_id'
                )
            ),
            array('table' => 'tags',
                'alias' => 'Tag',
                'type' => 'left',
                'conditions' => array(
                    'PostTags.tag_id = Tag.id'
                )
            )
        )
        ,'conditions' => array(
            'PostTags.post_id' => $id
        )
        ,'fields' => array(
            'Tag.title' // the name of the tag
        )
        ,'recursive' => -1
    );

    $tagsList = $this->Post->find('all', $options); 

    // added $result and foreach to ensure that all results would be printed
    $result = array();
    foreach ($tagsList as $tag):
        array_push($result, $tag['Tag']['title']);
    endforeach;

    $this->set('tags', $result);

    // ... rest of the call to find the post info
}

// Post's view.ctp
echo $this->Text->toList($tags);

Before I added $result, it would only print out the first association. I used "echo pr($tags);" in my view and found that the results I wanted were nested inside two arrays. After I added the foreach, it would correctly list all of the assigned tags in my view.