I consider that @EmbeddedId is probably more verbose because with @IdClass you cannot access the entire primary key object using any field access operator. Using the @EmbeddedId you can do like this: @Embeddable class EmployeeId { name, dataOfBirth } @Entity class Employee { @EmbeddedId EmployeeId employeeId; … } This gives a clear notion of the … Read more
Sometimes you have two entities and there’s a relationship between them. For example, you might have an entity called University and another entity called Student and a University might have many Students: The University entity might have some basic properties such as id, name, address, etc. as well as a collection property called students that … Read more
Either way will add an entity to a PersistenceContext, the difference is in what you do with the entity afterwards. Persist takes an entity instance, adds it to the context and makes that instance managed (i.e. future updates to the entity will be tracked). Merge returns the managed instance that the state was merged with. … Read more