What is the role of the Transactional annotation in working with Spring Data to ensure transaction management?

The @Transactional annotation in Spring Data is used for managing transactions at the method or class level. It ensures that all operations within the annotated method are executed within a single transaction.

Main functions of @Transactional:

• Start of transaction: a transaction is automatically opened when entering the method.
• Commit: if the method completes successfully, changes are committed to the database.
• Rollback: if an exception occurs, the transaction is rolled back, preventing partial changes.

Example of usage:

@Service
public class UserService {

    @Transactional
    public void createUser(User user) {
        userRepository.save(user);
        // other operations that should be atomic
    }
}

Thus, @Transactional simplifies transaction management, ensuring data integrity and easing error handling.