presto-base-jdbc/src/main/java/io/prestosql/plugin/jdbc/JdbcColumnHandle.java/JdbcColumnHandle/getColumnMetadata
class JdbcColumnHandle:    public ColumnMetadata getColumnMetadata()
    {
        return ColumnMetadata.builder()
                .setName(columnName)
                .setType(columnType)
                .setNullable(nullable)
                .setComment(comment)
                .build();
    }