Re: COPY for CSV documentation - Mailing list pgsql-patches

From Bruce Momjian
Subject Re: COPY for CSV documentation
Date
Msg-id 200404121518.i3CFIEQ22929@candle.pha.pa.us
Whole thread Raw
In response to Re: COPY for CSV documentation  (Bruno Wolff III <bruno@wolff.to>)
List pgsql-patches
Bruno Wolff III wrote:
> On Mon, Apr 12, 2004 at 10:30:22 -0400,
>   Bruce Momjian <pgman@candle.pha.pa.us> wrote:
> >
> > It is my understanding that \N is a valid column value (no backslash
> > escape in CSV, right?), so we can't use it for NULL.
> > The only thing I can think of is for NULL to be:
> >
> >     ,,
> >
> > (no quotes) and a zero-length string to be:
> >
> >     ,"",
> >
> > How do most applications handle those two cases?  If they accept either,
> > can we use that so we can read our own CSV files without losing the NULL
> > specification?
>
> I think the above are going to be treated as equvialent by most CSV parsers.
>
> There doesn't seem to be a standard for CSV. From what I found describing
> it, there isn't any feature for distinguishing NULLs from empty strings.
> So whatever gets done is going to be application specific.

I am thinking we could enable this NULL handling by default, and allow
it to be over-ridden with the NULL keyword.

--
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