@Override
    public ResultSet getImportedKeys(String catalog, String schema, String table) throws SQLException {
        //Return an empty result set with the required columns
        log.warn("getImportedKeys is not supported and may return invalid results");
        try {
            String sql = "SELECT NULL AS PKTABLE_CAT, " +
                    "NULL AS PKTABLE_SCHEM, " +
                    "NULL AS PKTABLE_NAME, " +
                    "NULL AS PKCOLUMN_NAME, " +
                    "NULL AS FKTABLE_CAT, " +
                    "NULL AS FKTABLE_SCHEM, " +
                    "NULL AS FKTABLE_NAME, " +
                    "NULL AS FKCOLUMN_NAME, " +
                    "NULL AS KEY_SEQ, " +
                    "NULL AS UPDATE_RULE, " +
                    "NULL AS DELETE_RULE, " +
                    "NULL AS FK_NAME, " +
                    "NULL AS PK_NAME, " +
                    "NULL AS DEFERRABILITY LIMIT 0";
            return connection.createStatement().executeQuery(sql);
        } catch (Exception e) {
            throw ExceptionUtils.toSqlState(e);
        }
    }
Returns name of the ClickHouse table types as the broad category (rather than engine name).
@return - ResultSet with one column TABLE_TYPE
@throws SQLException - if an error occurs
jdbc-v2/src/main/java/com/clickhouse/jdbc/metadata/DatabaseMetaDataImpl.java