Example: Read-read consistency checking

Read-read consistency checking only applies to LifeTimeInCache beans whose data is read from another transaction.

Usage scenario

For the Access Intents that are for repeatable read (RR), this means the product checks that the data is consistent with that in the data store and ensures that no one updates it after the checking. For the Access Intents that are for read committed (RC), this means the product checks that the data is consistent at the point of checking, but it does not guarantee that the data does not change after the checking. This makes the behavior of the LifeTimeInCache bean the same as non-LifeTimeInCache beans.

You have three options for setting consistency checking, as shown in the following scenarios concerning the calculation of interest in "Ann's" bank account. In each case, the data store is shared by this EJB CMP application (to calculate the interest) and other applications, such as EJB BMP, JDBC, or legacy applications. Also in each case, the EJB Account is configured as a “long-lifetime” bean.

NONE

Read-read checking AT_TRAN_BEGIN

Read-read checking AT_TRAN_END




Related concepts
Enterprise beans
Concurrency control
Related tasks
Developing applications that use JNDI
Related reference
WebSphere extensions to the Enterprise JavaBeans specification
Best practices for developing enterprise beans
Enterprise beans: Resources for learning
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Last updatedLast updated: Aug 30, 2013 4:53:43 PM CDT
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