Rails - Jul 2005 - object level transactions

How are object level transaction different from normal transactions?? 
Is there more or less protection in either case?

Object-level transactions

You can enable object-level transactions for Active Record objects,
though. You do this by naming the each of the Active Records that you
want to enable object-level transactions for, like this:

  Account.transaction(david, mary) do
    david.withdrawal(100)
    mary.deposit(100)
  end

If the transaction fails, David and Mary will be returned to their
pre-transactional state. No money will have changed hands in neither
object nor database.

On Friday 29 July 2005 23:14, Brian Lin wrote:
> How are object level transaction different from normal transactions??
> Is there more or less protection in either case?
Object-level transactions work purely in Ruby, the database is not 
involved. It''s a while since I looked into it, but I think at the 
beginning of a transaction block, a snapshot is taken of the objects 
given as arguments. In case the transaction is rolled back, these 
objects are restored from the snapshots.

Whether this is more or less protection than db transactions I can''t 
say. It depends on what you want. In the case of db-only transactions, 
your Ruby objects may have changed in the transaction block and stay 
that way after the block, even though the transaction was rolled back.

Michael

-- 
Michael Schuerig                            This is not a false alarm
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http://www.schuerig.de/michael/                      --Rush, Red Tide