Re: Output filter for psql - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: Output filter for psql
Date
Msg-id 4980DEDA.7060609@dunslane.net
Whole thread Raw
In response to Re: Output filter for psql  ("D'Arcy J.M. Cain" <darcy@druid.net>)
List pgsql-hackers

D'Arcy J.M. Cain wrote:
> On Wed, 28 Jan 2009 14:08:54 -0500
> Andrew Dunstan <andrew@dunslane.net> wrote:
>   
>> D'Arcy J.M. Cain wrote:
>>     
>>> I suppose we could define another line with options that we could
>>> define for meta information such as the border setting and the table
>>> name and whatever we define later.  E.g:
>>>
>>> "table:person","border:3","funky:option with \":\""
>>>       
>> Why do you want to add this extra information? psql doesn't output it 
>> now, and IIRC your original proposal didn't do it either.
>>     
>
> It mentioned including meta information.  I'm not sure that I really
> care if I get it but we may want it in general, if not now then later,
> and it would be something that would be extremely hard to retrofit.  If
> we start out with just the table and perhaps the border setting we can
> always add more later if we find we need it.  If we don't start with
> something then adding an extra line later will cause all sorts of
> heartache.
>
>   

For CSV it's likely to cause a headache right at the start. CSV with a 
single header line is a well known and mostly understood format. I don't 
know of any CSV processor (including ours) that handles more than one 
header line.

This is actually an example of why XML is not such a bad choice. It is 
rich enough that a processor is unlikely to be confused by metadata, and 
capable of being turned into almost any other format you might want with 
little  difficulty.

cheers

andrew


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