This query: "UPDATE table_name SET column_name=$inputUpdate[0] WHERE column_name=$input[1]" can update more than one rows at once! Probably it is not what you want. There some unique index column must be used for update.

I suggest to have two hashes: %input, and %inputUpdate instead of arrays. Those hashes contain ColumnName => value pairs.

Than, assuming ID is identity column:

my %update =
      map {$_ => $inputUpdate{$_} } 
        grep {$inputUpdate{$_} ne $input{$_} }
          keys %input;

$dbh->do(<<"SQL", undef, values %update, $input{ID});
update  TableName
   set @{[ join ', ', map {"$_ = '?'"} keys %update]}
 where ID = ?
SQL
$dbh->commit;
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