Can Entity Bean synchronize data when put across multiple apps server with no cluster

[Eric Pramono]

Guys..
I have a question that I need to figure out..
Can Entity Bean synchronize the data when it's being put across multiple application server with no clustering?
An example would be like this..
I have two application server containing the same exact Entity Bean viewing the same row in a table in one database. Then, illustrate the following sequence:
1. Entity Bean A reads the Data (say, equals to 13)
2. Entity Bean B reads the Data as well (13)
3. Then, B updates the Data to 17
The question is:
1. Would Entity Bean A know about the Data being updated to 17?
2. Is it allowed for the Entity Bean A to update the Data (which is invalid) to say, 16..? If it's allowed, then what happened with B? He wouldn't know if his update really means nothing..
Please let me know what you think, guys..
Since, I'm also a beginner in this J2EE..
Please remember that the environment consists of 2 application server and 1 database, and the Entity Bean lies across application server, and that we don't have any clustering (we use our own session manager to manage the session through database)..
Please let me know..
Thank you..
- eric

[Kyle Brown]

If you use Option C caching (e.g. NO caching) and you set the transaction isolation to serializable, then this will work without a problem since nothing will ever be cached...
Otherwise, you're hosed.
Kyle
[ March 11, 2002: Message edited by: Kyle Brown ]