I found a resolution. Its actually quite simple: just test for the length of the owner parameter and explicity asign undef if the length is 0. 
if (length($owner) > 0) {
    $case->owner( $q->param('owner') );
} else {
    $case->owner( undef );
}

[download]
Thanks for you assistance,
davidj

In reply to Re: class-dbi-mysql and null values by davidj
in thread class-dbi-mysql and null values by davidj

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