Function key_check_without_overlaps

sql/sql_table.cc:2850–2909

static
my_bool key_check_without_overlaps(THD *thd, HA_CREATE_INFO *create_info,
                                   Alter_info *alter_info,
                                   Key &key)
{
  DBUG_ENTER("key_check_without_overlaps");
  if (!key.without_overlaps)
    DBUG_RETURN(FALSE);
  // append_system_key_parts is already called, so we should check all the
  // columns except the last two.
  const auto &period_start= create_info->period_info.period.start;
  const auto &period_end= create_info->period_info.period.end;
  List_iterator<Key_part_spec> part_it_forwarded(key.columns);
  List_iterator<Key_part_spec> part_it(key.columns);
  part_it_forwarded++;
  part_it_forwarded++;
  while (part_it_forwarded++)
  {
    Key_part_spec *key_part= part_it++;

    if (period_start.streq(key_part->field_name)
        || period_end.streq(key_part->field_name))
    {
      my_error(ER_KEY_CONTAINS_PERIOD_FIELDS, MYF(0), key.name.str,
               key_part->field_name.str);
      DBUG_RETURN(TRUE);
    }
  }

  if (key.key_create_info.algorithm == HA_KEY_ALG_HASH ||
      key.key_create_info.algorithm == HA_KEY_ALG_LONG_HASH)

  {
    my_error(ER_KEY_CANT_HAVE_WITHOUT_OVERLAPS, MYF(0), key.name.str);
    DBUG_RETURN(TRUE);
  }
  for (Key &key2: alter_info->key_list)
  {
    if (key2.type != Key::FOREIGN_KEY)
      continue;
    DBUG_ASSERT(&key != &key2);
    const Foreign_key &fk= (Foreign_key&)key2;
    if (fk.update_opt != FK_OPTION_CASCADE)
      continue;
    for (Key_part_spec& kp: key.columns)
    {
      for (Key_part_spec& kp2: fk.columns)
      {
        if (kp.field_name.streq(kp2.field_name))
        {
          my_error(ER_KEY_CANT_HAVE_WITHOUT_OVERLAPS, MYF(0), key.name.str);
          DBUG_RETURN(TRUE);
        }
      }
    }
  }
  create_info->period_info.unique_keys++;