Why JPA repositories have to be linked to a transaction manager?

Question

I don't understand why JPA repositories have to be linked to a transaction manager.

@EnableJpaRepositories( basePackages = "com.ieci.mugeju.data.repositories1", entityManagerFactoryRef = "entityManager1", transactionManagerRef = "transactionManager1")

If I do this, any method I execute from these repositories will be executed with the transaction manager called "transactionManager1".

Suppose I define a second transaction manager and the following service class:

@Service
public class TestDenunciasServiceImpl implements TestDenunciasService
{
  @Autowired
  private Repository1 repository1;

  @Override
  @Transactional (readOnly = false, transactionManager = "transactionManager2")
  public void test ()
  {     
      MyEntity entity = new MyEntity ();
      ... call setters ...

      repository2.saveAndFlush(entity);
  }
}

Although we have used the @Transactional annotation to say that we want the test method to be executed in the transactionManager2 context, the entity is inserted using transactionManager1

How can I define a repository independently of a transaction manager? I would like transactions to be determined using the @Transactional annotation.

I would like the saveAndFlush method of the repository to be executed in the transaction of the transaction manager indicated through the @Transactional annotation

Answer 1

Linking JPA repositories to a transaction manager ensures proper transactional behavior, simplifies transaction management, maintains data integrity, and provides performance optimisations through caching.

It allows developers to focus on business logic while delegating transaction handling and persistence context management to the underlying framework.