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From Craig L Russell <Craig.Russ...@Sun.COM>
Subject Re: Migrating ejb 2.1 entity beans to jpa in weblogic
Date Tue, 25 Mar 2008 16:50:46 GMT
Hi Charlie,

On Mar 25, 2008, at 6:44 AM, Charlie Walker wrote:

> Hi Craig,
> Thanks for the help.  Let me see if I understand correctly.
>
> 1.  our oracle 10g database only supports "read committed",  
> "serializable"
> and "read only" tranasction isolation levels.
> 2.  on the "write side", issuing an entitymanager.flush(), forces the
> changes to the database.
>
> my question: "I thought since the underlying database is set to
> "read-committed", after executing the flush, only connections within  
> the
> current transaction would be able to read the changes to the  
> database until
> commit time."  Is this correct?

That's my understanding as well. And that's what I thought you were  
asking for. It exactly matches the behavior you described for "set  
delay-updates-until-end-of-tx to false".

If you want dirty reads, the database has to support the read- 
uncommitted isolation level. Are you migrating from a database that  
supports read-uncommitted?

Regards,

Craig
>
>
>
> Hi Charlie,
>>
>> If you're looking for the "write side" of the issue, try issuing an
>> EntityManager.flush() to force writing changes to the open  
>> connection.
>> Then, any connection with read uncommitted semantics will see the
>> changes.
>>
>> I don't know how to handle the "read side" if you cannot set read
>> uncommitted on the connection properties.
>>
>> Craig
>>
>> On Mar 24, 2008, at 3:03 PM, Charlie Walker wrote:
>>
>>
>
>
> -- 
> Charlie Walker - Registered Linux User #62358
>
> "Now and then we had a hope that if we lived and were good, God  
> would permit
> us to be pirates." - Mark Twain

Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:Craig.Russell@sun.com
P.S. A good JDO? O, Gasp!


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