Re: Atomic operations?

On 18-Mar-08, at 10:12 AM, Paul Tomblin wrote:

> On Tue, Mar 18, 2008 at 10:06 AM, Dave Cramer <pg@fastcrypt.com>
> wrote:
>> On 18-Mar-08, at 9:40 AM, Paul Tomblin wrote:
>>> I'm doing a simple delete/insert on a table, rather than trying to
>>> figure out whether the row exists or not and then doing an update or
>>> an insert.  But what I'm discovering is that every now and then I
>>> get
>>> a duplicate primary key exception, so I figure that two processes
>>> are
>>> doing the deletes and inserts and stomping on each other.  So my
>>
>> Can't you just check the return value from the delete to see if
>> anything was deleted ?
>
> I'm not sure how that would help.  If I do the delete and it didn't
> delete anything, that doesn't tell me if some other process inserted
> it in the meantime.
>
which ever process succeeds in deleting should do the insert.

Dave
>
>
>
> --
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> betters and my equals in my Calling here assembled, praying that in
> the hour of my temptations, weakness and weariness, the memory of this
> my Obligation and of the company before whom it was entered into, may
> return to me to aid, comfort and restrain.