I have applied a more limited patch that mentions this. I do not want
to mention _why_ we do not implement it because it is partly performance
and partly complexity, I think, and some combinations make no sense,
like temporary primary and non-temp foreign.

---------------------------------------------------------------------------

Jim C. Nasby wrote:
> On Sun, Oct 30, 2005 at 05:31:07PM -0800, Josh Berkus wrote:
> > Folks,
> >
> > Thanks, all! Now, if only I could remember who asked me the question ...
>
> ISTM we should add a note about this to the docs...
>
> Here's a patch for create_table.sgml, though there's probably some other
> places this could go...
> --
> Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
> Pervasive Software http://pervasive.com work: 512-231-6117
> vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461

[ Attachment, skipping... ]

>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: explain analyze is your friend

--
Bruce Momjian | http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073

Index: doc/src/sgml/ref/create_table.sgml
================================================== =================
RCS file: /cvsroot/pgsql/doc/src/sgml/ref/create_table.sgml,v
retrieving revision 1.94
diff -c -c -r1.94 create_table.sgml
*** doc/src/sgml/ref/create_table.sgml 13 Aug 2005 02:48:18 -0000 1.94
--- doc/src/sgml/ref/create_table.sgml 31 Oct 2005 18:11:27 -0000
***************
*** 421,427 ****
primary key of the <replaceable
class="parameter">reftable</replaceable> is used. The
referenced columns must be the columns of a unique or primary
! key constraint in the referenced table.
</para>

<para>
--- 421,429 ----
primary key of the <replaceable
class="parameter">reftable</replaceable> is used. The
referenced columns must be the columns of a unique or primary
! key constraint in the referenced table. Note that foreign key
! constraints may not be defined between temporary tables and
! permanent tables.
</para>

<para>


---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match