CakePhp does update instead of insert new data - php

Question

i started using cakephp, but now i encountered a problem which i am not able to solve.
I have got the following model relations which are relevant:
Exercise hasMany Points
Student hasMany Points,
now i want to check in the studentsController if for every exercise there is a Point data set, and iff not insert a new one.
When starting with no Point datasets, the function adds a new Point dataset for the first exercise correct, but after this it only updates the erxercise_id of this dataset, instead of creating new ones.
The controller function looks like this:
public function correct($id = null) {
$this->Student->id = $id;
$this->Student->recursive = 2;
if ($this->request->is('get')) {
$data = $this->Student->Exam->Exercise->find('all');
foreach($data as $exercise)
{
$exerciseID = $exercise['Exercise']['id'];
$this->Student->Point->recursive = 0;
$foundPoints = $this->Student->Point->find('all', array('conditions' => array('exercise_id' => $exerciseID)));
if($foundPoints == null)
{
$emptyPoints = array ('Point' => array(
'exercise_id' => $exerciseID,
'student_id' => $id
)
);
$this->Student->Point->save($emptyPoints);
}
else{
}
}
}
else //POST
{
}
}

Answer 1

if you have to insert a data you to use create() method like this:
This is only an example, with this line you create every time a new record into your database
and save data
$this->Student->Point->create();
$this->Student->Point->save($emptyPoints);

Answer 2

$this->Student->Point->id = '';
$this->Student->Point->save($emptyPoints);
or
$this->Student->Point->saveAll($emptyPoints);