Special handling of ConstraintViolationException after failed insert in JPA transaction

Vote count:

0

I want to do a couple of db-operations in a single transaction. It should be rolled back on all failures but one: in the middel of all the db-ops there will be an insert statement which inserts a generated number into a field that has an unique constraint. If this insert fails because the generated number is already present, in should be repeated with a newly generated number until it succeeds. But this insert should not affect the other operations.

Since there are no nested tx in JPA, i am not sure what the best practice would be here. i am wondering if this is such an uncommon case.

I tried it with an "embedded" tx, which is opened with requires-new that suspends the surrounding tx and resumes it after successfully inserting the random number. That worked partially: if there is an exception in the surrounding tx, everything is rolled back but the random number insert.

If i use one single tx, I don't know how i should determine why this tx failed to commit. so i don't know if i have to repeat all the operations with a new random number or leave it because of another failure.

I also tried to explicitely flush the entity manager session after the insert to force the exception before i continue with the rest of the work in hope i could just delete that entity from the EM programmatically and try again. But I didn't find a way to remove that entity from the EM after a failed insert?

I am also using Spring and SpringDataJPA.

@Transactional
public void doSomeThing() {

    SomeEntity fooEntity = new SomeEntity()
    someEntityRepository.save(fooEntity);

    someMoreDbOPs();

    RandomNoEntity rndEnt = new RandomNoEntity();
    while (true) {
            try {
                    rndEnt.setRandomNumber(generateRandomNumber());
                    entityManager.persist(rndEnt);
                    entityManager.flush();
                    break;
            } catch (ConstraintViolationException)
            {
                    //entityManager.detach(rndEnt); // didnt work
                    //entityManager.remove(rndEnt); // didnt work
            }
    }

    SomeEntity barEntity = new SomeEntity()
    someEntityRepository.save(barEntity);

    someMoreDbOPs();
}

i hope this pseudo code helps to describe what i am trying to do.

thanks in advance for any help...

asked 59 secs ago

gofrm

21

Special handling of ConstraintViolationException after failed insert in JPA transaction