Cakephp2不能显示来自容器的数据

我正在开发一个web应用程序使用蛋糕php 2。

我有一个问题，而显示数据从2个表…

My models:

<?php 
    class Discipline extends AppModel{
        public $hasMany = "Student";
    }
?>
<?php 
    class Student extends AppModel{
        public $belongsTo = array(
            "Discipline" => array(
                "className" => "Discipline",
                "foreignKey" => "discipline_id"
            )      
        );
    }
?>

这是我的studentscontroller:

<?php
class StudentsController extends AppController{
    function admin_index(){
        if($this->request->is('put') || $this->request->is('post')){
            $student = $this->request->data['Student'];
            if($this->Student->save($this->request->data)){
                $this->Session->setFlash("L'eleve a bien été modifié","notif");
            } 
        }
        $d['student'] = $this->Student->find('all',array(
            'contain' => "Discipline"
        )); 
        $this->set($d);
    }
}

我正在尝试使用这个视图显示学生的数据:

<?php
foreach($student as $k => $v){ 
    $v = current($v);
    echo "<td>Action</td>";
    echo "<td>Label</td>";
    echo "<td>".$v['nom']." ".$v['prenom']."</td>"; 
    echo "<td>".$v['sexe']."</td>"; 
    echo "<td>".$v['naissance']."</td>"; 
    echo "<td>".$v['Discipline']['designation']."</td>"; 
    echo "<td>".$v['comite']."</td>"; 
    echo "<td>".$v['classe']."</td>"; 
    echo "<td>".$v['elite']."</td>"; 
    echo "<td>".$v['alerte']."</td>"; 
    echo "<td>".$v['quota1']."</td>"; 
    echo "<td>".$v['quota2']."</td>"; 
    echo "<td>".$v['total']."</td>"; 
    echo "<td>Pris</td>"; 
    echo "<td>Restant</td>"; 
    echo "<td>Supp</td>"; 

}
?> 

但是我在这一行有一个问题:

 echo "<td>".$v['Discipline']['designation']."</td>";

显示如下错误:

notice (8): Undefined index: designation [APP'View'Students'admin_index.ctp, line 47]

我习惯在cakephp 3上开发，我对这个错误感到非常尴尬。如何从学生视图中显示学科表中的数据?

你知道吗?Thx

编辑:我在我的StudentsController上做了一个调试，我找到了我想显示的数据:

array(
    'student' => array(
        (int) 0 => array(
            'Student' => array(
                'id' => '2',
                'prenom' => 'Jean',
                'nom' => 'Michel',
                'sexe' => '1',
                'naissance' => '2015-08-02',
                'age' => '12',
                'classe' => '1',
                'discipline_id' => '1',
                'comite' => 'test',
                'categorie' => 'test',
                'elite' => true,
                'alerte' => 'test',
                'quota1' => '12',
                'quota2' => '12',
                'total' => '24',
                'note' => 'tete'
            ),
            'Discipline' => array(
                **'id' => '1',
                'designation' => 'Alpin'**
            )
        )
    )
)

foreach($student as $k => $value){ 
    $v = current($value);

foreach($student as $k => $v){ 
    $v = current($v);

echo "<td>".$v['Discipline']['designation']."</td>"; 

echo "<td>".$value['Discipline']['designation']."</td>";