Thank you, it makes the concept clearer to me. I think I need to look up the
source code for some details.
> 在 2018年5月13日，下午10:42，Jörn Franke <jornfra...@gmail.com> 写道：
>
> In detail you can check the source code, but a Serde needs to translate an
> object to a Hive object and vice versa. Usually this is very simple (simply
> passing the object or create A HiveDecimal etc). It also provides an
> ObjectInspector that basically describes an object in more detail (eg to be
> processed by an UDF). For example, it can tell you precision and scale of an
> objects. In case of ORC it describes also how a bunch of objects (vectorized)
> can be mapped to hive objects and the other way around. Furthermore, it
> provides statistics and provides means to deal with partitions as well as
> table properties (!=input/outputformat properties).
> Although it sounds complex, hive provides most of the functionality so
> implementing a serde is most of the times easy.
>
>> On 13. May 2018, at 16:34, 侯宗田 <zongtian...@icloud.com> wrote:
>>
>> Hello,everyone
>> I know the json serde turn fields in a row to a json format, csv serde turn
>> it to csv format with their serdeproperties. But I wonder what the orc serde
>> does when I choose to stored as orc file format. And why is there still
>> escaper, separator in orc serdeproperties. Also with RC Parquet. I think
>> they are just about how to stored and compressed with their input and output
>> format respectively, but I don’t know what their serde does, can anyone give
>> some hint?
