As a reminder I will list here the possible transaction models. The aim is not to be exhaustive, but merely to have this entry to check the possible transactions.
First, let's list the different models:
- Flat transactions (supported by J2EE)
- Nested Transactions (supported by J2EE)
- Chained Transactions
- Sagas
Flat transactions
Flat transactions consists of a series of operations which should be performed as one unit of work, and return true or false depending on whether the operation failed or not.
The reasons causing a transaction to abort may be for instance:
- some invalid parameters have been given to the components
- some system state which should not have changed, was violated
- Hardware or software failure
Nested transactions
Contrary to flat transactions, nested transactions allow to have units of work consisting of other atomic units of works. Some of the embedded unit of work may roll back without forcing the entire transaction to roll back. In that way, failed transactions can be performed again.
Note that subtransactions of transactions may also be nested transactions.
Chained transactions
In the chained transaction model, new transactions are started automatically for a program when the previous one has been commited or aborted.
This is not implemented by j2ee.
Long Running Transactions - Sagas
Sagas, or Long-Running transactions are transactions which may take a long time to finish and
may last for days either because they wait for an external event, or they wait for the decision of one of the actors involved in the transaction. This type of transaction usually occurs in a web service context (see
here).
This is not implemented by j2ee.
