<?php
/** application/libraries/MY_Form_validation **/
class MY_Form_validation extends CI_Form_validation
{
    public $CI;
    public $_field_data         = array();
    public $_config_rules       = array();
    public $_error_array        = array();
    public $_error_messages     = array();
    public $_error_prefix       = '<p>';
    public $_error_suffix       = '</p>';
    public $error_string        = '';
    public $_safe_form_data     = FALSE;

    /**
     * Is Unique
     *
     * Check if the input value doesn't already exist
     * in the specified database field.
     *
     * @param   string
     * @param   string  field
     * @return  bool
     */
    public function is_unique($str, $field)
    {
        sscanf($field, '%[^.].%[^.]', $table, $field);
        if ($this->CI->db !== NULL)
        {
            $query = $this->CI->db->limit(1)->get_where($table, array($field => $str));
            return $query->num_rows() === 0;
        }
        return FALSE;
    }
}