[Dbix-class] Pointless update on a date field

[Richard Jones]

In my Catalyst app, a method is looking for a partial match on an 
existing record, then updating the record with missing data, ie

my $user = $c->model('Schema::User');

if ( my $partial_match = $user->find( $search_for_missing{gender} ) ) {
     # record matched on last_name, first_name, dob, etc, but ! gender
     $user->update( $form_data ); # should just update gender field
}

All appears to be working fine, but I notice from the debugging SQL that 
the date field (dob) is always updated, even though the submitted value 
is identical to the stored value of the retrieved record, ie:

UPDATE users SET dob = ?, gender = ? WHERE ( id = ? )

I assume this is because I am using InflateColumn::DateTime on the date 
fields. If I dump $user->last_name I get a scalar, but $user->dob gives 
me a complex data structure (the DateTime object?). But I'm not sure why 
it is trying to update the date field. Presumably it's harmless, as the 
update would silently fail anyway?

The question is, am I correct, and do I need to worry about it?
-- 
Richard Jones