public function _unique_field(Validate $array, $field)
{
if ($array[$field]) {
$query = DB::select($this->_fields[$this->_primary_key]->column)->from($this->_table)->where($this->_fields[$field]->column, '=', $this->_fields[$field]->_database_wrap($array[$field]))->execute($this->_db);
if (count($query)) {
$array->error($field, 'unique');
}
}
}