Entity beans provide us a view of persistent object.
Design your object model. Then you can judge whether you need it or not.
If you only have a database view, session beans is not needed in the your logic.
You are correct. Entity Beans are not required if you choose not to use them. Session Beans with a DAO is a valid implementation of a persistence layer, and should involve the use of Value Objects (serialised Java objects) to pass data between your various tiers.
You should only use Entity Beans when you have fully considered the pros and cons of the technology, and decided that it fits your system architecture and design approach. Don't use Entity Beans if your only reason is "because I can".
Thanks for all your response!
It seems that the DAO works as the BMP EntityBean.You need to write SQL statement by yourself.What's the difference between the DAO and BMP EntityBean?