Re: SQL design pattern for a delta trigger?

--- Erik Jones <erik@myemma.com> wrote:

>
> On Dec 6, 2007, at 2:36 PM, Ted Byers wrote:
>
> [snip]
> What you want to do here for handling the update v.
> insert is called
> an "UPSERT".  Basically, what you do is run the
> update as if the row
> exists and catch the exception that is thrown if it
> doesn't at which
> point you insert the record with the end date =
> now().  After that
> you can proceed normally with creating the new
> record with start date
> = now() and end date = NULL.
>
Thanks Eric.  Do you know of an URL where this is
discussed or where I can find an example.  None of my
books discuss this, and my search using google has so
far produced only noise.

Thanks again.

Ted