Question

Sorry if this is obvious – I’m trying to do a find() on a join table and failing, whats the correct syntax to do this?

Basically I have expenseCode table with a HABTM releationship with the expense table.

In my expenseCode model I have:

public function beforeDelete($cascade  = false) {

    $count = $this->Expense->find("count", array(
        'conditions' => array('expense_code_id' => $this->id)
    ));

    if ($count == 0) {
        return true;
    } else {
        //$this->Session->setFlash('Record cannot be deleted as it has ' . $count . 'number of expenses attached to it');
        return false;
    }

}

If I uncomment the setFlash() I get the error.

Where am I going wrong? Thanks in advance.

Answer 1

Unfortunately it’s not possible to perform such a query on the HABTM join table from one of the parent models without some extra work. I’m assuming that Expense is the parent model and ExpensesCode the join model?

A common way is to modelise the HABTM join table. Say you have an expenses and codes table which are joined by expenses_codes:

$this->Expense->bindModel(array('hasOne' => array('ExpensesCode')));
$this->Expense->find('all', array(
  'fields' => array('Expense.*'),
  'conditions' => array('ExpensesCode.expense_code_id' => $this->id)
));

However, Cake also auto-iniatlises a model for the join table when a HABTM association is defined (see the manual, and the “with” key in the list of possible keys).

So this syntax would let you directly query the join table:

$this->Expense->ExpensesCode->find('all', array(
  'conditions' => array('ExpensesCode.expense_code_id' => $this->id)
));

The query above will net you with an array containing only the results from the join table, as it doesn’t perform a join like the first procedure. So you would have to perform a second find() on the Expense model to find the expenses related to the expense_code_id from ExpensesCode.

EDIT:
It’s a framework convention that HABTM join tables should be underscored and alphabetically ordered. So if the HABTM join table is called codes_expenses, it’s auto-modelised as CodesExpense.