Re: Conditional INSERT: if not exists

> If you know there won't be concurrent inserts or deletes affecting the
> row of interest there is a way to do this in the INSERT statement.

I cannot rule out concurrent inserts.

> > transaction...I'm not sure the nested transaction is necessary...maybe
> > just the savepoint. Example:
> Using save points creates nested transactions, so you have that overhead by
> whatever name it is called.

Overhead yes, that was not the question.  The question was is the
extra nesting necessary?