Know about transaction process through this ppt.

2.  Because failures occurs, transaction are broken up
into states to handle various situation.
 Active, the initial state; the transaction stays in
this state until while it is still executing.
 A transition is terminated only if it has either been
committed or aborted.

3.  The DBMS needs to write out enough information to
disk so that, in case of a failure, the system could re-create
the updates performed by the transaction once
the system is brought back up. After it has written out
all the necessary information, it is committed.

4.  Committed- after successful completion.
 Once committed, the transaction can no longer be
undone by aborting it.
 Its effect could be undone only by a compensating
transaction.

5.  Aborted, after the transaction has been rolled
back the the database has been restored to its state
prior to the start of the transaction.
 The DBMS could either kill the transaction or
restart the transaction.
 A transaction may only be restarted as a result of
some hardware or software error, and a restarted
transaction is considered a new transaction.

6.  Thus the possible sequence of states are:
 Active -> Partially committed -> Committed
 Active -> Partially committed -> Aborted
 Active -> Failed -> Aborted

8. Ravi Ranjan MCA- I Iyr