Data::Transactional provides data structures with RDBMS-like transactional
abilities, so changes can be rolled back.  A very primitive earlier attempt
at the same problem is also included, Tie::Hash::Transactional.

To install, perform the usual dance of:

    perl Makefile.PL
    make
    make test
    make install

Also included in this distribution is a plugin for Data::Compare so that
it does (what I think is) the Right Thing when looking at Data::Transactional
objects.  See:

   perldoc Data::Compare::Plugins::Data::Transactional and
   perldoc Data::Compare

for details.

Please note that Tie::Hash::Transactional is DEPRECATED.  It will be
removed at some point in the future.