Transaction Isolation Levels

[Anup Batra]

Hi Ranchers,
I am not able to understand the difference between the Transaction isolation levels i.e the difference between Read Committed and Serializable. I have also read the documentation but the difference is not clear especially about the Serializable. Can any one pls help me in this matter.
Thanks in Advance,
Anup Batra

[Beksy Kurian]

"serializable transaction" means that a
query only see the data that was commited before the query starts
and all the data modified by its own transaction. "Read commited" means that the query
can only see the data that was commited before the start. If you are giving the command "set transaction isolation level serializable", it influences only
the next transaction. After the transaction is committed, the isolation level
reverts to the default "read committed". If the "set transaction isolation
level serializable" statement is not executed again before the next transaction,
that transaction will have an isolation level of "read committed".
hope it helps!
Beksy