docs: public ResultSet getImportedKeys(String catalog, String schema, String table)
        throws SQLException {
  
      String database = catalog;
      // We avoid using information schema queries by default, because this appears to be an expensive
      // query (CONJ-41).
      if (table == null) {
        throw new SQLException("'table' parameter in getImportedKeys cannot be null");
      }
  
      if (database == null && connection.nullCatalogMeansCurrent) {
        /* Treat null catalog as current */
        return getImportedKeysUsingInformationSchema("", table);
      }
  
      if (database == null) {
        return getImportedKeysUsingInformationSchema(null, table);
      }
  
      if (database.isEmpty()) {
        database = connection.getCatalog();
        if (database == null || database.isEmpty()) {
          return getImportedKeysUsingInformationSchema(database, table);
        }
      }
  
      try {
        return getImportedKeysUsingShowCreateTable(database, table);
      } catch (Exception e) {
        // Likely, parsing failed, try out I_S query.
        return getImportedKeysUsingInformationSchema(database, table);
      }
    }