How to select PROPAGATION in spring transaction?

Question

I am just reading the spring-mybatis.xml,here are some code of transaction-manager:

I want to know why some methods defines as "REQUIRED" or "SUPPORTS"?How to think about it and decide which to choose?

Answer 1

Your question is, I think it's about Spring transaction and it's depend on your business logic and how you can control spring transaction.

To understand the Spring transaction "REQUIRED" or "SUPPORTS", you need to understand spring transaction definition. This transaction definition types are come from org.springframework.transaction.TransactionDefinition class. But first you need to understand 1)Spring transaction types and then 2)Spring transaction Definition.

1) Spring supports two types of transaction management:
Programmatic transaction management: This means that you have manage the transaction with the help of programming. That gives you extreme flexibility, but it is difficult to maintain.

Declarative transaction management: This means you separate transaction management from the business code. You only use annotations or XML based configuration to manage the transactions.

2) Spring Transaction Definition
PROPAGATION_REQUIRED： Spring REQUIRED behavior means that the same transaction will be used if there is an already opened transaction in the current bean method execution context. Create a new one if none exists. In short this means that if an inner(2nd Transaction) method causes a transaction to rollback, the outer(1st Transaction) method will fail to commit and will also rollback the transaction.
PROPAGATION_SUPPORTS: Support a current transaction; execute non-transactionally if none exists.

Understandanding these "REQUIRE" "SUPPORTS" is not enough, as I mentioned to you that you need to understand all Spring definition under org.springframework.transaction.TransactionDefinition class.

Unfortunately, I had one power point about this Spring types and transaction which I wrote at Dec 2014 in slideshare website. Spring Transaction Management

In this slide, I added very important point about Spring transaction in power point note session. So please not only refer to slide content but also refer to slide note session. Hope it help.

Example, refer as power point notes session too for more understanding about Spring transaction definition.

Edited:
Propagation Means: Typically, all code executed within a transaction scope will run in that transaction. However, you have the option of specifying the behavior in the event that a transactional method is executed when a transaction context already exists. For example, code can continue running in the existing transaction (the common case); or the existing transaction can be suspended and a new transaction created. Spring offers all of the transaction propagation options familiar from EJB CMT. To read about the semantics of transaction propagation in Spring, see Transaction Propagation