Why not Replace?

[powerman]

Hmm..
Why not use REPLACE instead of UPDATE+INSERT?
The only problem with REPLACE is when you UPDATE not all fields in table, but for your example REPLACE is good.

$dbh->do("REPLACE INTO $table SET item_id=?, upc=?",
    undef, $item_id, $upc) or die $dbh->errstr;

[asdfgroup]

This won't work because of 2 resons :

1) This will work only for key field but this is not clear based on example item_id is keyfield

2) record can have additional fields. All this fields after replace will be empty