Magnus Hagander wrote:
> On Thu, Sep 3, 2009 at 13:31, Andrew Dunstan<[email protected]> wrote:
> >
> >
> > Magnus Hagander wrote:
> >>
> >> Oh, hang on, "the NULL string" refers to the copy parameter? Not a
> >> part of the data? I read it as "a string being NULL". Maybe something
> >> like "the value of the NULL string parameter" to be overly clear for
> >> people like me? :-)
> >>
> >
> > We could change:
> >
> > ? A NULL is output as the NULL string and is not quoted, while a data value
> > ? matching the NULL string is quoted.
> >
> >
> > to
> >
> > ? A NULL is output as the NULL parameter and is not quoted, while a non-NULL
> > data value whose text representation
> > ? matches the NULL parameter is quoted.
> >
> >
> > or something similar. Would that be better?
>
> Yes, much better IMO.
I have applied the attached documentation clarification patch, and
backpatched it to 8.4.X.
--
Bruce Momjian <[email protected]> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
Index: doc/src/sgml/ref/copy.sgml
===================================================================
RCS file: /cvsroot/pgsql/doc/src/sgml/ref/copy.sgml,v
retrieving revision 1.87
diff -c -c -r1.87 copy.sgml
*** doc/src/sgml/ref/copy.sgml 5 Sep 2009 23:58:01 -0000 1.87
--- doc/src/sgml/ref/copy.sgml 17 Sep 2009 21:06:59 -0000
***************
*** 550,562 ****
<para>
The <literal>CSV</> format has no standard way to distinguish a
<literal>NULL</> value from an empty string.
! <productname>PostgreSQL</>'s <command>COPY</> handles this by
! quoting. A <literal>NULL</> is output as the <literal>NULL</>
! string and is not quoted, while a data value matching the
! <literal>NULL</> string is quoted. Therefore, using the default
! settings, a <literal>NULL</> is written as an unquoted empty
! string, while an empty string is written with double quotes
! (<literal>""</>). Reading values follows similar rules. You can
use <literal>FORCE NOT NULL</> to prevent <literal>NULL</> input
comparisons for specific columns.
</para>
--- 550,559 ----
<para>
The <literal>CSV</> format has no standard way to distinguish a
<literal>NULL</> value from an empty string.
! <productname>PostgreSQL</>'s <command>COPY</> handles this using
! quoting. A <literal>NULL</> is output as an empty string without
! quotes, while an empty string data value is double-quoted
! (<literal>""</>). Reading values follows similar rules. You can
use <literal>FORCE NOT NULL</> to prevent <literal>NULL</> input
comparisons for specific columns.
</para>
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