如何在cakephp中找到关联表的最后一条记录？

Question

I am using cakephp 2.4.5. I want to find the last record of an associated table. Below is my code

    $Latest = $this->ParentModel->find('first',array(
                           'conditions' => array('ParentModel.id'=>$id),
                           'order' => array('ParentModel.AssociatedModel.id' => 'DESC')
                                                          ));    

This code has missing column error with ParentModel.AssociatedModel.id but the id column is definitely there. Does it look right in the first place? If not, how can I fix this part or is there a better implementation? Thank you

Answer 1

You can't do "cross conditions" though associated models, but you can use Containable behavior to filter associated models.

For this, you have to bind the behavior to your model through:

public $uses = array('Containable');

And then do your query:

$this->ParentModel->find('first', array(
    'conditions' => array('ParentModel.id' => $id),
    'contain' => array(
        'AssociatedModel' => array(
            'limit' => 1,
            'order' => array('id DESC')
        )
    )
));

This will give you the parent model, and the last associated model.

Answer 2

Have you tried to read the manual about retrieving data ? It is clearly explained there.

If AssociatedModel is somehow associated with one of the four association types with ParentModel, you'll have to use this syntax:

$Latest = $this->ParentModel->find('first',array(
   'contain' => array('AssociatedModel'),
   'conditions' => array('ParentModel.id' => $id),
   'order' => array('AssociatedModel.id' => 'DESC')
)); 

Make sure the other model is included by using recursive or contain(). See this page about Containable .

If your field name in the DB is really containing a dot CakePHP2 will have a problem with that because it uses the dot notation as separator. At least I've never used a dot in a database field, it's doable but doesn't make much sense and obviously breaks Cake, no idea if you can work around that.

Answer 3

I guess it should be like this

    $Latest = $this->ParentModel->AssociatedModel->find('first',array(
                       'conditions' => array('ParentModel.id'=>$id),
                       'order' => array('AssociatedModel.id DESC')
                                                      ));    

Check if it is correct.