Andrew Goedhart wrote:

> I don't think this would work. In my understanding if two transactions
> start
> at the same time, they would see a snapshot of the table as it existed at
> the start of the transactions. Thus both could insert because the
> Where clause on the insert would not see the other transactions changes.
> Even with no isolation it would still be problem because the physical time
> it takes for the server to do the select and then insert the record. Only
> solution I see unfortunately is a table lock.
>

Your analysis, sir, is correct in all regards.