How do the six transaction attributes map to isolation levels like "dirty

Question :How do the six transaction attributes map to isolation levels like "dirty
read"? Will an attribute like "Required" lock out other readers until I'm
finished updating? (EJB)
Answer :The Transaction Attributes in EJB do not map to the Transaction Isolation
levels used in JDBC. This is a common misconception. Transaction
Attributes specify to the container when a Transaction should be started,
suspended(paused) and committed between method invocations on
Enterprise JavaBeans. For more details and a summary of Transaction
Attributes refer to section 11.6 of the EJB 1.1 specification.