CakePHP pass a array to paginate() - new model - cakephp

Question

Hi I've done a find() and added a new field to some of the results:
$approved = $this->ExpenseClaim->find('all', array('conditions'=> array('ExpenseClaim.claim_status_id' => '3')));
$i = 0;
foreach ($approved as $ap) {
$approved[$i]['ExpenseClaim']['claimTotal'] = $this->ExpenseClaim->expenseClaimTotal($approved[$i]['ExpenseClaim']['id']);
$i++;
}
I now need to pass this to paginate, however I read here that you cannot do this and that I must create another model to use the afterFind() method only on this one particular find.
So I've created the new Model called ExpenseClaimTotal and set the UseTable to
public $useTable = 'expense_claims';
Then in the new models afterFind() method I did a simple debug:
public function afterFind($results, $primary = false) {
debug($results);
//return $results;
}
But when I now try and do a find against this new model in pagesController it fails:
$this->loadModel('ExpenseClaimTotal');
$approved = $this->ExpenseClaimTotal->find('all', array('conditions'=> array('ExpenseClaim.claim_status_id' => '3')));
This is the error I get:
Database Error
Error: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'ExpenseClaim.claim_status_id' in 'where clause'
SQL Query: SELECT `ExpenseClaimTotal`.`id`, `ExpenseClaimTotal`.`user_id`, `ExpenseClaimTotal`.`claim_status_id`, `ExpenseClaimTotal`.`created`, `ExpenseClaimTotal`.`modified`, `ExpenseClaimTotal`.`approved`, `ExpenseClaimTotal`.`approved_by`, `ExpenseClaimTotal`.`declined_by`, `ExpenseClaimTotal`.`date_submitted` FROM `expenses`.`expense_claims` AS `ExpenseClaimTotal` WHERE `ExpenseClaim`.`claim_status_id` = 3
There doesnt seem to be much in the docs about using 2 models for one table

Answer 1

You don't want to paginate an array
You're already performing a find, it's not sensible to perform a find and then paginate the resultant array.
Simply paginate your model data directly and inject your total values in the process. As such - if you put your original "added a new field to some of the results" logic in the model:
class ExpenseClaim extends AppModel {
public function afterFind($results, $primary = false) {
foreach ($results as &$ap) {
if (isset($ap['ExpenseClaim']['id'])) {
$ap['ExpenseClaim']['claimTotal'] = $this->expenseClaimTotal($ap['ExpenseClaim']['id']);
}
}
return $results;
}
}
Your controller code becomes simply:
public function index() {
$conditions = array('ExpenseClaim.claim_status_id' => '3');
$data = $this->paginate($conditions);
$this->set('data', $data);
}
And the code is simple and "just works".
Enhancements
The above is the simplest way to achieve the desired results, but has some disadvantages - namely it will call the total method on pretty much all finds.
Depending on exactly what you're doing you may wish to for example:
Cache your totals
If appropriate, you can remove problems by simply adding the field "claim_total" to the database, and recalculate whenever it changes. That would mean there is absolutely no extra logic when reading from the expense claim model.
Use a custom find type
If you don't want to recaculate the total on all finds - you can create a custom find type
class ExpenseClaim extends AppModel {
public $findMethods = array('allWithTotals' => true);
protected function _findAllWithTotals($state, $query, $results = array()) {
if ($state === 'before') {
return $query;
}
foreach ($results as &$ap) {
$ap['ExpenseClaim']['claimTotal'] = $this->expenseClaimTotal($ap['ExpenseClaim']['id']);
}
return $results;
}
And then use it in your paginate call:
public function index() {
$this->paginate['findType'] = 'allWithTotals'; # <-
$conditions = array('ExpenseClaim.claim_status_id' => '3');
$data = $this->paginate($conditions);
$this->set('data', $data);
}
In this way, only the index method will trigger the call to add the totals.