The @Transactional annotation in Spring is used to manage transaction boundaries for methods in Spring beans. It helps ensure that a series of operations within a method occur within a single database transaction, which either completes successfully or rolls back entirely if any error occurs. Here's when to use it:
Multiple Database Operations When you have multiple database operations (like save(), update(), or delete()) in a method, and you want to ensure they are either all executed successfully or none at all (atomicity), you should use @Transactional. This ensures consistency and prevents partial updates in case of failure.
Handling Rollbacks You should use @Transactional when you want automatic rollback in case of exceptions. By default, Spring rolls back on unchecked exceptions (RuntimeException) but not on checked exceptions. You can customize rollback behavior using the rollbackFor or noRollbackFor attributes.
Read-Write Operations When your method performs both read and write operations on the database, marking it @Transactional ensures that all operations occur in a single transaction and maintain data consistency.
Lazy Loading (Hibernate) If you're using Hibernate and want to use lazy-loaded entities, the @Transactional annotation ensures that the session remains open during method execution, allowing lazy loading to fetch data from the database when needed.
Propagation and Isolation Levels You can configure transaction propagation (how transactions behave in relation to other transactions) and isolation levels using @Transactional. This is useful in complex systems where transactions interact in different ways.
Managing Complex Rollbacks and Exception Handling You should use @Transactional when you have complex rollback rules or need fine control over exception handling in transactional contexts.