A question about JPA Cascade and removing entity

Question

I have two entities called User and UserProfile in my data model. Here is how they are mapped.

Code from User Entity:

@OneToOne(cascade=CascadeType.ALL)
@P         


        

Answer 1

Your question is wrong in and of itself, which is where all the confusion stems from. Arthur did a good job with his answer but it's clear from the comments the the confusion still remains so let me take a stab at it here.

Do cascades hold only when I specify them on the entity owning the relationship?

"cascade" is an attribute you specify on one (or possibly both in case of bi-directional) end of a relationship. It determines what actions performed on that end will be propagated to the other end. There are many different types of those actions defined in JPA and even more defined in Hibernate extensions. This distinction is important - you should only talk about specific behavior being propagated and not "cascade" in general.

PERSIST, MERGE, REFRESH propagate normally (from the end they were declared on to the other).

REMOVE, however, is tricky because it can mean two different things. If you have a relationship between A and B and you're trying to remove A, you can either remove B on the other end OR you can remove the association but leave B intact. Hibernate makes a clear distinction between the two - you can declare REMOVE (DELETE) and DELETE_ORPHAN cascade types separately; JPA spec does not. Note that DELETE_ORPHAN is not supported to single-valued relationships (OneToOne / ManyToOne).

Thus, propagation of REMOVE (by itself or when it's part of ALL) depends on whether relationship has a clear owner (uni-directional always does; bi-directional does if it's mapped using mappedBy and does not if it's mapped via join table) in which case it's propagated from owner to owned OR no owner in which case it's propagated in either direction but without DELETE_ORPHAN semantics unless it was explicitly specified. Typical example of the latter is bi-directional many-to-many.