On 7/13/06, Chris Hoover <[EMAIL PROTECTED]> wrote:
On this table, I have created a unique index on payer_trn03, payer_trn04,
and expire_timestamp. However, since the expire_timestamp is normally null,
the unique index does not appear to be working. I have been able to enter
two identical rows into this table.
Why is PostgreSQL not enforcing this index? This appears to be a pretty
major a bug? It would seem that you could have a unique index across
columns that might have a null in them.
From:
http://www.postgresql.org/docs/8.1/interactive/indexes-unique.html
Quote:
"When an index is declared unique, multiple table rows with equal
indexed values will not be allowed. Null values are not considered
equal. A multicolumn unique index will only reject cases where all of
the indexed columns are equal in two rows."
Regards,
Rodrigo
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