Re: Unique constraint and NULL values

"Mark C. Stock" <mcstockX_at_Xenquery .com> wrote in message news:zsqdnU_QrsleJurcRVn-vA_at_comcast.com...
|
| "Agoston Bejo" <gusz1_at_freemail.hu> wrote in message
| news:cl8ba7$d04$1_at_news.caesar.elte.hu...
| | I want to enforce such a constraint on a column that would ensure that
the
| | values be all unique, but this wouldn't apply to NULL values. (I.e.
there
| | may be more than one NULL value in the column.)
| | How can I achieve this?
| | I suppose I would get the most-hated "table/view is changing,
| | trigger/function may not see it" error if I tried to write a trigger
that
| | checks the uniqueness of non-null values upon insert/update.
| |
| |
|
| did you try a standard UNIQUE constraint on the column?
|
| unlike SQL-Server (unless they've changed it since I last worked on it),
| Oracle processes null values properly in this scenario (i.e., one NULL
value
| is never consider equal to another NULL value)
|
| ++ mcs
|
|

group: sorry for not noticing the overloading on the OP and clearing it out before I responded Received on Thu Oct 21 2004 - 08:40:30 CDT