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question on concurrency control, transaction, BMT

 
Ying Zhou
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hey guys:
sorry about the subject, I am have some trouble understand transaction.
Okay, in EJB transaction, there is "I" for isolation. I read "Enterprise JavaBean 3rd" book, it give lots details on those isolation levels.
The part I dont quite understand is, if I am doing BMT, so is it to developer's responsibility to provide isolation control? Do I have to say, get a JDBC connection and call setTransactionLevel, then start using the connection do all my work?
Also, I am using weblogic6.1, anyone happens to know how am I able to control isoaltion level in CMT?
Well, I get in some trouble on how to control the concurrenly accessing data. Any help is highly appreciated.

Regards

Ying
 
Hari babu
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When you are BMT,you specify the transaction boundaries, but if you want the the transaction (unit of work which is inside the boundary) to be free from the concurrency problem, you need to specify the ISOLATION level in your deployment decriptor. If you are using weblogic you need to specify the ISOLATION level in your weblogic-ejb-jar.xml file (check the DTD). You need code the ISOLATIOn levels in your bean implementation, you just need to specify in the descriptor and the container should take care of managing the ISOLATION levels.
Also 1 question i have is, If the ISOLATION level is an EJB spec why should we specify in the application server specific ejb-jar.xml files. what i feel is we should be specifying the same in bean's ejb-jar.xml file.
 
Ying Zhou
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Thanks for the feedback, yes, you are right, I double checked weblogic's doc, it covered this part, for both CMT and BMT.
Now I need read more detail on bea's website.
btw, you are the 2nd person i know last name is babu, the 1st is that poor restraunt owner in Singfield show
Thanks a lot!
Ying
 
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