This naive use of ->in_storage leads to a race condition:

sub insert_row {
  my ($self, $run) = @_;

  if ($run->in_storage) {
    return;
  } else {
    # race condition here
    $run->insert;
    return 1; # ???
  }
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Part of the problem is that the Oracle driver throws an exception for primary key violations. Catching that exception requires that I know what the exception looks like, and that leads to the Oracle-specific code.

If, for instance, $run->insert returned false if the insert failed for a unique index violation, then I could write database independent code.