Re: Patch: FORCE_NULL option for copy COPY in CSV mode

On Fri, Oct 11, 2013 at 12:49 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> On Thu, Oct 10, 2013 at 6:45 PM, Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:
>>
>> On 10/09/2013 11:47 PM, Amit Kapila wrote:
>>>
>>>
>>> One of the advantage, I could see using "NULL For .." syntax is
>>> that already we have one syntax with which user can specify what
>>> strings can be replaced with NULL, now just to handle quoted empty
>>> string why to add different syntax.
>>>
>>> "FORCE_NULL" has advantage that it can be used for some columns rather
>>> than all columns, but I think for that existing syntax can also be
>>> modified to support it.
>>>
>>>
>>>
>>
>>
>> I think it's badly designed on its face. We don't need and shouldn't
>> provide a facility for different NULL markers. A general facility for that
>> would be an ugly an quite pointless addition to code complexity. What we
>> need is simply a way of altering one specific behaviour, namely the
>> treatment of quoted NULL markers. We should not do that by allowing munging
>> the NULL marker per column,
>
> I was thinking it to similar in some sense with "insert into tbl"
> statement. For example
> Create table tbl (c1 int, c2 int, c3 int, c4 int)
> insert into tbl (col2) values(1);
>
> Here after table name, user can specify column names for which he
> wants to provide specific values.
>
>> but by a syntactical mechanism that directly
>> addresses the change in behaviour. If you don't like "FORCE NULL" then let's
>> pick something else, but not this ugly and unnecessary "NULL FOR" gadget.
>
> If you don't like idea of one generic syntax for NULLs in COPY
> command, then "FORCE_QUOTED_NULL" or "QUOTED_NULL" will make more
> sense as compare to FORCE_NULL.

Meh. As amused as I am with our bad naming, I don't think there's
anything too terribly wrong with FORCE NULL. Symmetry has some value.

--
Robert Haas
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