extract ORC contents without printing into strings first

[Zhiyuan Dong <zh...@gmail.com>]

Hi ORC gurus,

When I study the file contents example using C++ ORC api, it uses printer
utility to print row contents into a string for selected columns for each
row. My question is : is printing into a string is the only way that we can
access ORC file contents ? Is there an example that I can follow that can
directly read some selected column contents into vectors, e.g. integer,
float, string, without printing into string first and then parse the string
back into corresponding data types, e.g integer, float, string ?

2nd question ; is there a column reader class that can read an entire
column into a vector ? If so, is there any code example ?

Best,

Zhiyuan

Re: extract ORC contents without printing into strings first

[Gang Wu <us...@gmail.com>]

Yes, you can find the example in https://orc.apache.org/docs/core-cpp.html

Calling orc::RowReader::next() will return the orc::ColumnVectorBatch data
which has a specific batch for each type. All the public APIs that you can
have is here: https://github.com/apache/orc/tree/master/c%2B%2B/include/orc


Let me know if you have any question.

Best,
Gang

On Thu, Nov 15, 2018 at 8:23 PM Zhiyuan Dong <zh...@gmail.com> wrote:

> Hi ORC gurus,
>
> When I study the file contents example using C++ ORC api, it uses printer
> utility to print row contents into a string for selected columns for each
> row. My question is : is printing into a string is the only way that we can
> access ORC file contents ? Is there an example that I can follow that can
> directly read some selected column contents into vectors, e.g. integer,
> float, string, without printing into string first and then parse the string
> back into corresponding data types, e.g integer, float, string ?
>
> 2nd question ; is there a column reader class that can read an entire
> column into a vector ? If so, is there any code example ?
>
> Best,
>
> Zhiyuan
>