Serkan, It is generally a bad idea to lock rows for a period that spans user think time. In your case, the client could forget he|she has locked data, go for a cup of coffee or the client app itself could crash. In this case, the DB Admin would have to manually kill the hanging transaction or set a transaction timeout.
A better solution would be a versioning mechanism to ensure that users do not overwrite each other's data. See the thread: http://swjscmail1.java.sun.com/cgi-bin/wa?A2=ind0106&L=ejb-interest&P=R23083 for some details on how this could be implemented. -krish > -----Original Message----- > From: A mailing list for Enterprise JavaBeans development > [mailto:[EMAIL PROTECTED]]On Behalf Of Serkan Oktar > Sent: Thursday, March 07, 2002 1:16 PM > To: [EMAIL PROTECTED] > Subject: basic transaction management and isolation level question > > > Hi, > > Although I ve written many many pages about EJB I could'nt suceed to clarify > some very basic points. In order simplifying the case I created an example.. > Can anyone make a suggestion for this case. I need help becasuse I am > totally blocked at this point. > > Assume we have a session bean (S) and two entity beans (A,B). There should > be two basic methods in session bean S's remote interface, one for getting > data (readData()) and one for updating (updateData()). > > Both of these methods should access the entity beans A and B. Remote > interfaces of them will be accesses by calling findByPrimaryKey() methods, > data will be read by getter methods in readData() and updated by setter > methods in updateData(). > > My question is about transaction management. How can I gurantee that the > data read in readData method will be locked till the updateData method > terminates. Assume data collected are represented on a GUI and client waits > N seconds and then triggers updateData method. > > 1) Which transaction attributes and isolation levels should be selected for > session Bean S,entity bean A,B and more importantly for methods readData() > and update Data()? I think there should be a transaction which begins with > readData and ends with updateData(). > > 2) More basic question about session Bean. Should it be stateless or > statefull? I could'nt find a solution because I am doing the same job in > both cases.. > > Thanks for everyone who has read this and more thanks who can save me , > Serkan > > =========================================================================== > To unsubscribe, send email to [EMAIL PROTECTED] and include in the body > of the message "signoff EJB-INTEREST". For general help, send email to > [EMAIL PROTECTED] and include in the body of the message "help". > > =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff EJB-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".
