Function check_duplicate_key

sql/sql_table.cc:2505–2542

Check if there is a duplicate key. Report a warning for every duplicate key. @param thd Thread context. @param key Key to be checked. @param key_info Key meta-data info. @param key_list List of existing keys. */

  @param key_list         List of existing keys.
*/
static void check_duplicate_key(THD *thd, const Key *key, const KEY *key_info,
                                const List<Key> *key_list)
{
  /*
    We only check for duplicate indexes if it is requested and the
    key is not auto-generated.

    Check is requested if the key was explicitly created or altered
    by the user (unless it's a foreign key).
  */
  if (key->old || key->type == Key::FOREIGN_KEY || key->generated)
    return;

  for (const Key &k : *key_list)
  {
    // Looking for a similar key...

    if (&k == key)
      break;

    if (k.generated ||
        (key->type != k.type) ||
        (key->key_create_info.algorithm != k.key_create_info.algorithm) ||
        (key->columns.elements != k.columns.elements))
    {
      // Keys are different.
      continue;
    }

    if (std::equal(key->columns.begin(), key->columns.end(), k.columns.begin(),
                   key_cmp))
    {
      push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE, ER_DUP_INDEX,
                          ER_THD(thd, ER_DUP_INDEX), key_info->name.str);
      return;
    }
  }
}


bool Column_definition::prepare_stage1_typelib(THD *thd,