my $parentId = $q->param('annual');
   my $thisSession = $q->param('id');

   tie my %obj, 'Tie::DBI', $dbh, 'conference_event','id', { CLOBBER => 1, WARN => 1, DEBUG => 1, CASESENSITIV => 1 } ;
   my @keys;

   if ( ! $thisSession ) {
      my $tempId = (keys %obj)[-1];
      @keys = keys %{ $obj{$tempId} };
      $thisSession = $tempId + 1;
   } else {
      @keys = keys %{ $obj{$thisSession} };
   }

   my $newVals;
   foreach my $key ( @keys ) {
     $newVals->{$key} = $q->param($key) ||
                           $obj{$thisSession}->{$key};
   }

   $newVals->{'id'} = $thisSession;
   $newVals->{'conf_annual_id'} = $parentId;

   ## $obj{$thisSession} = $newVals;
   $obj{'id'} = $newVals;


##</code><code>##


Ignored attempt to change value of key field "id" at ... (line #)
insert into table ....
update table set ....