Re: Unique Index - Mailing list pgsql-general

From Roman Neuhauser
Subject Re: Unique Index
Date
Msg-id 20050119163503.GC74874@isis.wad.cz
Whole thread Raw
In response to Unique Index  (Alex <alex@meerkatsoft.com>)
Responses Re: Unique Index  ("J. Greenlees" <jaqui@telus.net>)
List pgsql-general
# alex@meerkatsoft.com / 2005-01-20 01:35:32 +1100:
> i have a unique index on a table over multiple columns. If now one of
> the records has a null value in one of the indexed columns i can insert
> the same record multiple times.
>
> Is this a problem within postgres or expected?

    In SQL, NULL means "unknown value". How could you assert that two
    NULLs are equal?

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