In standard SQL using PCC, the transaction isolation level defines the degree to which data can be accessed by other users during the transaction. For example, the isolation level “repeatable reads” locks all rows or pages read during the transaction. After one query in the transaction has read rows, no other transaction can update or delete the rows until the repeatable-reads transaction completes.
When using OCC, EAServer supports a logical isolation level that provides the same semantics as the corresponding PCC isolation level, while allowing safe use of OCC optimizations such as avoiding row locks and query results caching.
Logical isolation levels supported by EAServer are listed in the description of the ejb.isolationLevel Ant property—see “Commonly configured properties” in Chapter 2, “Deploying and Configuring EJB Components,” in the Enterprise JavaBean User’s Guide.
