You're welcome! Lukas
Am 26.03.2010 um 17:51 schrieb Andras Hatvani: > Lukas, > > thanks for the prompt and detailed answer! > > Cheers, > Andras > > On 2010 Mar 26, at 17:15, Lukas Lang wrote: > >> Hey Andras, >> >> great to see another group of students participating! >> >> Regarding your question: >> After committing the first transaction, the object's state is transferred to >> the database (eventually flushed), the transaction cache is invalidated and >> the object tracker (which identifies changes within objects) stops >> "following" the Person instance. In terms of JPA: It becomes detached. >> >> When starting the second transaction, Castor (the running transaction in >> specific) has no clue that your Person instance wants to contribute to that >> transaction (Imagine Castor keeping references to all objects someone had >> loaded from the database earlier would not be such a good idea, especially >> from the garbage collection's point of view and concerning database locks >> etc.). >> >> However, you have two options: >> >> 1) Load the entity, then modify it and then commit the transaction. >> 2) Explicitly calling Database.update using Long Transactions as described >> in [1]. >> >> I hope that all your questions are now answered. Feel free to follow up, if >> not. >> >> Regards, >> Lukas >> >> PS: One more thing: ad "persisted value remains the same". Always perform a >> flush first, because it simply may have not been flushed! >> >> [1] Long Transactions, http://castor.org/long-transact.html >> >> Am 26.03.2010 um 16:39 schrieb Andras Hatvani: >> >>> Hi, >>> >>> I'm new to Castor and I'm part of this semester's development team of the >>> course Advanced Software Engineering on the Vienna University of Technology. >>> During the development with Castor the following question arose for me: Why >>> must the load and the updating of an object be in the same transaction? >>> >>> Example: >>> 1) WORKS >>> db.begin(); >>> loadedPerson = db.load(Person.class, id); >>> loadedPerson.setFirstName(FIRST_NAME_2); >>> db.commit(); >>> >>> 2) DOESN'T WORK >>> db.begin(); >>> loadedPerson = db.load(Person.class, id); >>> db.commit(); >>> >>> db.begin(); >>> loadedPerson.setFirstName(FIRST_NAME_2); >>> db.commit(); >>> >>> In the second case the persisted values remained the same. >>> >>> Thanks, >>> Andras Hatvani >>> >>> >>> --------------------------------------------------------------------- >>> To unsubscribe from this list, please visit: >>> >>> http://xircles.codehaus.org/manage_email >>> >>> >> >> >> --------------------------------------------------------------------- >> To unsubscribe from this list, please visit: >> >> http://xircles.codehaus.org/manage_email >> >> > > > --------------------------------------------------------------------- > To unsubscribe from this list, please visit: > > http://xircles.codehaus.org/manage_email > > --------------------------------------------------------------------- To unsubscribe from this list, please visit: http://xircles.codehaus.org/manage_email
