Re: how to overwrite tuples in a table

"Pradeepkumar, Pyatalo (IE10)" wrote:
> No I am not looking for UPDATE command.For updating first i should check if
> there is a tuple with the given pointid and attributeid, if present then i
> should use the UPDATE command.....thats fine. But what I wanted was a
> situation wherein, I will blindly call the insert command and the database
> takes care of overwriting the previous values.....is that possible.

I suggest you just try the UPDATE command, and if that
fails, perform an INSERT. You have to lock the table,
in case another process is trying to do the same thing
at the same time.

(Unfortunately, you cannot use a transaction, because
the failing UPDATE would abort the transaction. However,
I believe the nested-transaction feature of PostgreSQL 8
(still in beta) would allow to do such things. Someone
please correct me if I'm wrong ...)

Best regards
Oliver

--
Oliver Fromme, secnetix GmbH & Co KG, Oettingenstr. 2, 80538 München
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