Paginate from within a model in CakePHP

问题:

I have a function in my Event model called getEvents - you can pass limit, start and end dates, fields, event types, and event subtypes.

I read that paginate can accept all the parameters I'm using like joins, conditions, limit...etc just like a normal find can.

It returns data just fine when I don't try to paginate. But - I'd like to be able to pass it a paginate variable to tell it instead of doing this:

$this->recursive = -1;
$data = $this->find('all', $qOptions);

to do this:

$this->recursive = -1;
$data = $this->paginate($qOptions);

When I try that, though, it gives me lots of errors. I can specify the errors later if needed - for now, I guess I'm looking for - is this something that can be done? If so, how?

Is there another better way to do something like this? I spent enough time making this function do just what I want, and allowing all the options passed...etc - it just seems like a waste if I can't also use it for pagination. But - if it's not ideal, I'm ok hearing that too. Thanks in advance.

EDIT:

I'm reading other things online that say you shouldn't use paginate in your model, because it draws from URL variables, which defeats the MVC structure purpose. This makes sense, but does that mean I have to write the same joins/queries in both model and controller? And in every action that it's needed?

回答1:

The way I figured out how I can keep my complex find in my model without having to rewrite it a second time in the controller is by passing a $paginate boolean variable.

If $paginate is true, it returns just the options created, which can then be used in the controller's pagination. If it's false (meaning we don't want to paginate), it returns the actual event results. So far this seems to be working.

In my getEvents() function (this method is in the Events model)

    if($paginate) {
        return $qOpts; // Just return the options for the paginate in the controller to use
    } else {
        $data = $this->find('all', $qOpts); // Return the actual events
        return $data;
    }

Then, in my Events/Index (events controller, index action - where I know I want pagination):

$this->Event->recursive = -1; // (or set recursive = -1 in the appModel)
$opts['paginate'] = true;

$paginateOptions = $this->Event->getEvents($opts);

$this->paginate = $paginateOptions; // Set paginate options to just-returned options
$data = $this->paginate('Event'); // Get paginate results
$this->set('data', $data); // Set variable to hold paginated results in view

回答2:

The paginate() model method does not accept the same parameters as a find(). Specifically, find() wants an array of options, but paginate() wants every option passed individually. See Custom Query Pagination in the CakePHP book.

So, instead of:

$data = $this->paginate($qOptions);

You want something like:

$data = $this->paginate($qOptions['conditions'], $qOptions['fields'], ...);

EDIT

Custom model pagination isn't a function that you call. It's a function that you need to implement and will be called by the CakePHP framework. In the example in your question you are trying to manually call $this->paginate(...) from somewhere in your model. That doesn't work. Instead, do this.

In your model, implement the paginate and paginateCount methods.

function paginate($conditions, $fields, ...)
{
    // return some data here based on the parameters passed
}

function paginateCount($conditions, ...)
{
    // return some rowcount here based off the passed parameters
}

Then, in your controller you can use the standard pagination functions.

function index()
{
    $this->paginate = array('MyModel' => array(
        'conditions' => array(...),
        'fields' => array(...),
    ));

    $this->set('myobjects', $this->paginate('MyModel'));
}

Now, the Controller::paginate() function will grab the conditions and other data from the Controller::paginate parameter and, instead of passing it to your Model::find it will pass it to your custom Model::paginate() and Model::paginateCount() functions. So, the data that is returned is based on whatever you do in those two methods and not based on a standard find(). }

回答3:

you can use this one which is working fine for me.

$condition="your where condition"; $this->paginate = array( 'fields' => array('AsinsBookhistory.id', 'AsinsBookhistory.reffer_id', 'AsinsBookhistory.ISBN','AsinsBookhistory.image','AsinsBookhistory.title','AsinsBookhistory.last_updatedtime'), 'conditions' => $condition, 'group' => array('AsinsBookhistory.ISBN'), 'order' => array('AsinsBookhistory.last_updatedtime' => 'desc') ); $this->set('lastvisitedbooks', $this->paginate('AsinsBookhistory'));

回答4:

$paginate array are similar to the parameters of the Model->find('all') method, that is: conditions, fields, order, limit, page, contain, joins, and recursive.

So you can define your conditions like this :

var $paginate = array(
 'Event' => array (...)
 );

Or you can also set conditions and other keys in the $paginate array inside your action.

 $this->paginate = array(
 'conditions' => array(' ... '),
 'limit' => 10
 );
 $data = $this->paginate('Event');

• http://book.cakephp.org/2.0/en/controllers.html
• http://book.cakephp.org/2.0/en/core-libraries/components/pagination.html

R u using $name = 'Event' in your controller ?

If we wont mention model name in $this->paginate() , it will use model as mentioned in $name otherwise look in var $uses array and in that will get Model name (first one )

for e.g var $uses = array('Model1','Model2'); // $name != mentioned

n you want pagination with respect to Model2 then you have to specify ModelName in paginate array like $this->paginate('Model2') otherwise Model1 will be considered in pagination.