Cakephp Model with multiple status - php

Question

I'm asking myself something... Here is the question :
I have a model Request. This model has a status. (let's say it is an integer)
As the status will change through the time AND as I want to keep a record of each changes this was pretty clear in my mind that the status will not be a field of the Request table/model.
I thought I will add a table/model RequestStatus and say to CakePHP
Request hasMany RequestStatus
Then I thought that it will be simple to retrieve all the Request that has a valid status only.
But I was wrong.
Using containable is not good as it retrieve the Request even if they have a wrong status (or even if they don't have a status).
So, I tested 2 solutions :
Binding on the fly the RequestStatus model as a hasOne relation but
it not works as expected
Use a joins key/array when making my find call.
There is clearly something that I missed because, this is not working.
Am I missing something ? Or the best way to do it is by having a status field in the Request table ?
EDIT : What I forgot to mention is that I need to use this query with the pagination of CakePHP

Answer 1

I will assume a couple of things you didn't mention. First of all, I suppose you also created a RequestStatus belongsTo Request relationship. And I imagine your RequestStatus table have four columns: id, status, request_id and created. The request_id column is the foreign key and created is the magic field that CakePHP populates when a new row is created. I also assume you are using Containable behaviour.
With that, you can go three different ways:
1) You can retrieve last valid Statuses along with their Requests.
In your RequestModel:
public function getValidRequests() {
$db = $this->RequestStatus->getDataSource();
$subquery = $db->buildStatement(array(
'fields' => array('request_id', 'max(created) as lastcreated'),
'table' => $db->fullTableName($this->RequestStatus),
'alias' => 'temp',
'group' => array('request_id')
), $this->RequestStatus);
return $this->RequestStatus->find('all', array(
'contain' => array('Request'),
'joins' => array(
array(
'table' => '(' . $subquery . ')',
'alias' => 'rs2',
'type' => 'right',
'conditions' => array(
'RequestStatus.request_id = rs2.request_id',
'RequestStatus.created = rs2.lastcreated'
)
)
),
'conditions' => array('RequestStatus.status' => 1),
'order' => array('RequestStatus.request_id' => 'desc')
));
}
2) You can retrieve all Requests with their Status, then return only those with last valid status.
In your RequestModel:
public function getValidRequests() {
$requests = $this->find('all', array(
'contain' => array(
'RequestStatus' => array(
'order' => array('RequestStatus.created' => 'desc')
)
)
));
$result = array();
foreach ($requests as $request) {
if ($request['RequestStatus'][0]['status'] == 1)
$result[] = $request;
}
return $result;
}
3) Denormalization.
Add a last_status column in your Request table. So every time you update a request's status, insert that new status into your RequestStatus table and save that new status to Request.last_status. Now you can simply do:
public function getValidRequests() {
return $this->find('all', array(
'conditions' => array('Request.last_status' => 1)
));
}