Database Software

Hi Folks,

I would like to know the difference between these 2 ways of deallocating the unused space.
Can you please provide me the details?

way1:
alter table table_name deallocate unused;

way2:
alter table table_name enable row movement;
alter table table_name shrink space compact;
alter table table_name shrink space;
alter table table_name disable row movement;

Thanks