@EmbeddedId vs. @IdClass - when shall I use what?

[oskar.carlstedt]

Hi all!

Can anyone explain the difference between the two annotations @IdClass/@Id and @Embeddable/@EmbeddableId. When shall I use @IdClass and when shall I use @EmbeddedId?

Does anyone of you have a good answer to this? I would really appreciate your help to make me understand what decision to take in different situations.

Best Regards
/Oskar

[fhh]

IMHO @EmbeddedId should be used when the combined pk is either a meaningful entity itself or it reused in your code.

@IdClass is useful to specify that some combination of fields is unique but these do not have a special meaning.

Regards

Felix