Re: Extend COPY FROM with HEADER to skip multiple lines - Mailing list pgsql-hackers

On 2025/07/03 11:08, Shinya Kato wrote:
> On Wed, Jul 2, 2025 at 4:48 PM Fujii Masao <masao.fujii@oss.nttdata.com> wrote:
>
>>>> Regarding the documentation, how about explicitly stating that when MATCH is specified, only
>>>> the first line is skipped? While this may seem obvious, it’s worth clarifying, as the semantics
>>>> of the HEADER option have become a bit more complex with this change.
>>>
>>> Agreed.  I have updated the documentation as follows:
>>>
>>> +      lines are discarded.  If the option is set to <literal>MATCH</literal>,
>>> +      the number and names of the columns in the header line must exactly
>>> +      match those of the table and, in order, after which the header line is
>>> +      discarded;  otherwise an error is raised.  The <literal>MATCH</literal>
>>
>> How about making the wording a bit clearer? For example:
>>
>>       If set to MATCH, the first line is discarded, and it must contain column names that
>>       exactly match the table's columns, in both number and order; otherwise, an error is raised.
>
> Thank you for the review. I fixed it.

Thanks for updating the patch! I've pushed the patch.


>> Also, the phrase "if this option is set to..." is repeated three times in the current text.
>> For the second and third instances, we could simplify it to just "if set to...".
>
> Agreed. However, for the sake of symmetry between "On output" and "On
> input" and to maintain clarity between the paragraphs, I have omitted
> "this option is" from the "On input" paragraph only.

Yes, I agree that's better.

Regards,

--
Fujii Masao
NTT DATA Japan Corporation