[HACKERS] Unique functional index and FK constraints

2002-11-11 Thread Kris Jurka 
Tom,

When you restructured the unique index location and validation for
foreign key constraints around 9/22 you added the restriction that the
supporting unique index may not be functional.  I believe that this
restriction is not necessary.  Suppose I had a unique index on
LOWER(login).  That would imply that login is unique as well.  Any
function which returns different results given the same input is no good
for a functional index anyway.

http://archives.postgresql.org/pgsql-committers/2002-09/msg00293.php

Kris Jurka

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Re: [HACKERS] Unique functional index and FK constraints

2002-11-11 Thread Tom Lane 
Kris Jurka [EMAIL PROTECTED] writes:
 When you restructured the unique index location and validation for
 foreign key constraints around 9/22 you added the restriction that the
 supporting unique index may not be functional.  I believe that this
 restriction is not necessary.

Hmm ... I'm not convinced.  What about functions that return NULL for
some inputs?  A unique index will not reject multiple NULL entries.

regards, tom lane

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