在迁移时间上添加了codeigniter动态字段

Question

i have two database called "migrate_new" and "migrate_old" and both have one table called "cms_pages".

i want to compare "migrate_old" db "cms_pages" with the "migrate_new" "cms_pages" table structure if "migrate_new" database "cms_pages" does not have "field" then alter table automatically.

below is my code to compare "migrate_old" "cms_pages" fields not in "migrate_new" "cms_pages" now i want to add this fields on table. i want to continue the process in place of exit.

**> any one can have idea to add fields automatically so no need to stop migration task?

i am not able to get field details like type , key , etc. how i know alter table with use modify or add fields. i short i want to set structure with out loss of any data automatically. thanks in advance..
**

    $this->load->database();
    $admin_db = $this->load->database('ADMINDB', TRUE);

    $query = $this->db->get('cms_page');
    $result = $query->result();

    $fields_old = $this->db->list_fields('cms_page');
//  $fields_new = $admin_db->list_fields('cms_page');
    $flag = false;
    foreach ($fields_old as $field){

        if (!$admin_db->field_exists($field, 'cms_page'))
        {
            echo $field.'=> is not exists in new table please contact to developer for that <br>';
            $flag = true;
        }
    }

    if($flag){
        exit;           
    }