Design parent-child controllers - cakephp-2.0

Question

I am new to cakePHP and trying to get my head around the framework to see how to implement my requirements.
My application allows (admin) users to define Forms (parent) and FormElements (child) that later on will be composed on the fly and presented to the end-users.
To start prototyping I baked all the pieces and I can enter rows in both tables as expected.
edit to simplify the question:
The Forms controller already shows a list of Forms and when one is selected (view action), a list of the FormElements for that Form.
But... when I add a new FormElement, I have to select again a Form the Element will be associated to.
Instead I want the FormElements controller/model to know which Form was initially selected and fill the form_id automagically.
Is there a "best practice" approach on how to handle this ?
Just in case its needed:
CREATE TABLE IF NOT EXISTS `forms` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`description` varchar(60) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `form_elements` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`form_id` int(11) NOT NULL,
`name` varchar(40) NOT NULL,
`type` int(11) NOT NULL,
`widget` int(11) NOT NULL,
`mandatory` tinyint(4) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

Answer 1

This happens more often than you think. I had QuestionModel hasMany AnswerModel and wanted to add Answers within my AnswersController. I needed to show QuestionModel name and other attributes of the "parent" object. This is what my add action inside my AnswersController looks like:
public function add($question_id = null) {
$this->Answer->Question->id = $question_id;
if (!$this->Answer->Question->exists()) {
throw new NotFoundException(__('Invalid question'));
}
if ($this->request->is('post')) {
$this->request->data['Answer']['question_id'] = $question_id;
$this->request->data['Answer']['user_id'] = $this->Auth->user('id');
if ($this->Answer->save($this->request->data)) {
$this->Session->setFlashSuccess(__('Your answer has been saved'));
} else {
$this->Session->setFlashError(__('Your answer could not be saved. Please, try again.'));
}
$this->redirect(array('controller'=>'questions','action' => 'view', $question_id));
}
$question = $this->Answer->Question->read();
$this->set('question', $question);
}
You will notice that I am passing the Question.id to the AnswersController add action. Having this allows me to pull the Question from the DB and allows me to be able to redirect the user back to the specific question they were on before they clicked on "Add Answers to this Question".