Hi all
  In Enitity Bean,when any business method is called,
the container will call ejbLoad and ejbStore,is it right?
if the business method is not data access in Entity bean
,container still call ejbLoad and ejbStore ?
if it's so,it will make network heavy traffic,
if i use a session bean to access data by JDBC when i want to access database,
then why use Entity Bean? which good???

hi
you can restrict call to load and store by setting the
deployment descriptor,is-db-shared and is-modified-method-name,

and advantages of entity are multiple clients can acess the entity concurrently,
session bean use db call for every request where as entity
will cache your data in middle tier.

hope u got it,
bye
rk.

Hi
  thanks your reply the message! I can understand
the entity Bean catch data,but another Q is why define
the value object in Entity Bean?

and the "advantages of entity are multiple clients
can acess the entity concurrently",

All business methods in Entity Bean and Session Bean
 are called serializable ,is it right? if it is so
then what is "multiple clients can acess the
entity concurrently"
      Thanks

hi ,

you use value objects for bulk access of data to optimize performance,
that is all the passed to client with one remote call.

coming to concurrent acess
There can be more than one entity representing the same data and updating the database is locked by the isolation level opted.
Thus many users can access data with their own copies.


bye
Ravi.

Hi ravi kiran
  thanks for your reply,it is ok! i can understand
"There can be more than one entity representing
the same data",the container will guarantee the data
is same,Is it?

then i want to ask another Q: if the statless
session Bean also has more than one instance like
Entity Bean?

hi alix,
yes container will guarante that there is no data inconsistancies,

but coming to state less session bean its different because each client has one instance which is same like any other instance but there wont be any caching ,
that is every get and set need data access.

bye
rk.

Hi ravi kiran
   Thanks very much for your reply and every message
is in time. Maybe i dont express clearly for stateless session bean.
  if there are many many clients call a stateless
session Bean at the same time,the container only use
one stateless bean instance to serialize all clients
call (one by one) or there are many the same Bean
instance in container to response every client at the same
time?
   I have another Q(sorry so many Q):How to choice
Entity Bean and stateless Session bean for db access?
   if i want to do a bulk database query(100000 rows or
more),i should use a Entity Bean finder method or write
a stateless session bean for the big database table
(JDBC executeQuery),or write a common stateless session
bean to do all db table select,ex:
Vector query(String sql)

which one should i choice?
thanks!