This can be very difficult to get right. For example, Dominus's suggestion to use 
    eval { UPDATE ... } or INSERT ...;
introduces a potential race condition. If two processes are simultaneously trying to update-or-insert a row using that technique then the following can happen: 
(initially the row is not there)
process A: UPDATE fails
process B: UPDATE fails
process A: INSERT succeeds
process B: INSERT fails
causing an unexpected failure in one of the processes. It's safer to do it the other way around: 
eval { INSERT ... } or UPDATE ...;
which ought to be safe, because a successful INSERT will lock the affected row. I think this difficulty nicely illustrates the advantage of having a REPLACE option in EZDBI, though it would have to be implemented slightly differently for each different type of database.

In reply to INSERT or UPDATE by Anonymous Monk
in thread EZDBI is an easier interface to SQL databases by Dominus

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