我想在codeigniter中存储多行的爆炸值

Question

我想将逗号分隔值存储在多行的数据库中，这是我的代码

控制器

$mail_checkbox = $this->input->post('mail_chechbox');
if ($this->input->post('mail_chechbox') != "") {
    $id = '';
    foreach ($mail_checkbox as $row_id) {
        $id = $id . $row_id . ',';
    }
    $data['id'] = rtrim($id, ',');
    $ids = explode(',',$data['id']);

}

$admission_checkbox = $this->input->post('admission_nos');//echo $admission_no;exit; 
if ($this->input->post('admission_nos') != "") {
    $admissionno = '';
    foreach ($admission_checkbox as $admission_number) {
        $admissionno = $admissionno . $admission_number . ',';
    }
    $data['admissionnos'] = rtrim($admissionno, ',');
}

$data = array('student_id' =>$data['id'],'batch' => $batch,'roll_no' => $data['admissionnos'],'day' => $date_day,'month' => $date_month,'year' => $date_year );

$this->admin_model->attendance_entry($data);

这里我将所有逗号分隔值存储在一行中，但我希望字符串中的每个值都有不同行的存储。