php - cant add new record in HABTM table -

i want add new record in table called tutorssubject. table created habtm relationship of tutor , subject. anyway load subject names in text box , can select subject name cant add new record. need set id of tutor_id. there 3 fields in tutorssubject table called id,tutor_id , subject_id. need select in 1 field subject_id list of names found in subject table, , set tutor_id manually.

currently able select list of subject names cant add new record subject name , set tutor_id.

error: sqlstate[23000]: integrity constraint violation: 1452 cannot add or update child row: foreign key constraint fails

class tutorssubjectscontroller extends appcontroller {

public function tutoradd() {

 $this->loadmodel('subject');             $options['recursive']=-1;             $options['fields']=array('subject.name');           $te2= $this->subject->find('list',$options);      debug($te2);     $this->set( 'te',$te2);     //put edit , post new record     if ($this->request->is('post')) {            $this->request->data['tutorssubject']['tutor_id']=2;          debug($this->request->data);         if ($this->tutorssubject->save($this->request->data)) {             $this->session->setflash(__('your post has been updated.'));             return $this->redirect(array('controller' => 'tutors','action' => 'tutordetails'));         }         $this->session->setflash(__('unable update post.'));     }      //view works fine displays list             echo $this->form->create('tutorssubject', array('type' => 'post'));               echo $this->form->input('tutorssubject.subject_id', array('options' => $te));              echo $this->form->end('save post');  //model subject public $hasandbelongstomany = array(          'tutor' => array(             'classname' => 'tutor',             'jointable' => 'tutors_subjects',             'foreignkey' => 'subject_id',             'associationforeignkey' => 'tutor_id',             'unique' => 'keepexisting',             'conditions' => '',             'fields' => '',             'order' => '',             'limit' => '',             'offset' => '',             'finderquery' => '',             'deletequery' => '',             'insertquery' => ''         )     );  //model tutor   public $hasandbelongstomany = array(         'subject' => array(             'classname' => 'subject',             'jointable' => 'tutors_subjects',             'foreignkey' => 'tutor_id',             'associationforeignkey' => 'subject_id',             'unique' => 'keepexisting',             'conditions' => '',             'fields' => '',             'order' => '',             'limit' => '',             'offset' => '',             'finderquery' => '',             'deletequery' => '',             'insertquery' => ''         ),      );