Cascade Operations

Cascade propagates an operation to related Entities

Sometimes related objects form one lifecycle unit. For example, when a new order is saved, the line items created together with it may need to be saved as well. JPA lets you explicitly specify which operations should propagate across a relationship.

@OneToMany(mappedBy = "order", cascade = CascadeType.PERSIST)
private List<OrderItem> items = new ArrayList<>();

Now persist(order) can propagate the PERSIST operation to the elements of the items collection. Without cascade, related objects do not automatically participate in the same lifecycle operation just because a reference points to them.

Cascades are chosen according to relationship semantics

• PERSIST — propagate persistence;
• MERGE — propagate merge;
• REMOVE — propagate removal;
• REFRESH and DETACH — propagate the corresponding lifecycle operations;
• ALL — include all of the operations listed above.