A
There is no rule which states that when a transaction aborts the users must
be notified.
close B
If a transaction aborts, all of its changes are removed from the database.
That would be the exact opposite of this answer...
close C
Some transaction management systems (such as those which use immediate
writeback) can allow transactions to read data which other transactions have
changed but not committed. In those systems, if the first transaction fails
then all the transactions which have read data modified by that first
transaction must be undone, or "rolled back". However, this answer is
only true if the transactions in question were using such an environment, so
the answer is not always 100% true.
close D
Once a transaction commits then its changes cannot be aborted later.
close E
Transactions at the end of their lifespan must release all of their locks.
Locks cannot be maintained outside the scope of a transaction. Thus, whether
they abort or commit, all locks must be released.
close
When a transaction aborts
- all users must be notified
- all changes it has made are immediately available to other transactions
- the modifications of all transactions currently running are also aborted
- it can abort transactions which have already committed
- it releases all of its locks
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