http://www-900.ibm.com/developerWorks/cn/java/J-PATHCOL/
notes:
Entity Bean VS SessionBean JDBC
Read / write needs. The data that needs to be read frequently and the data from not change or occasionally changes is preferably handled by session beans with JDBC. Development work will be simply straight and produce excellent response time. If the data needs frequent updates and supports many concurrent requests (so there are many concurrent changes), the entity bean is an option. In the face of concurrency requests for data, it is too difficult to overcome the complexity involved in ensuring data integrity, synchronization, and frequent persistence, it is too difficult to overcome, and it is not worth spending time and effort to create it. Business support. The CMP entity bean makes developers don't have to care about the transaction environment. All transaction details are declared in the deployment descriptor of the bean. If you accept this level of control, the CMP entity bean will undoubtedly provide the easiest solution. If more control is needed, the BMP bean allows developers to define the operations that should be taken without having to write business rules for this type of operation. For maximum levels of control, session beans should be used. Session Bean manage complex transactions involving CMP and BMP entity beans, as well as a minority JDBC call. Listing time. The CMP entity bean is clearly the only listing time in all J2EE persistence mechanisms. Declare data types and names, define deployment settings, and then be responsible for the rest of the application server and supplier tools. It is difficult to say which BMP entity bean and session bean and JDBC combination can be row the second fast solution. On the one hand, BMP will be faster because the container is on behalf of Bean to provide so many lifecycle services. On the other hand, the session bean will lead because they do not have BMP, so the build / test / deployment cycle is shorter. Finally, in these three solutions for your specific items, they are sorted only part of the entire comparison process. This rating must also be targeted for the next category (resource usage). Resource usage. The entity bean is named due to a large number of resources (especially when concurrently requested concurrent requests). In contrast, the session bean and JDBC data source connections are very lightweight, only a small amount of server resources. For more information on this, please read the "J2EE Technologies for THE STATELESS NETWORK" in the first article "J2EE TECHNOLOGIES for THE STATELESS NETWORK". EJB-QL tutorial: http://www-900.ibm.com/developerWorks/cn/cnonlinetutorial.nsf/gethtml? OpenAgent & URL = / WebServices / WS-WSComp3 / Tutorial / WS-wscomp3-3 -3.html
