Planned lessonJNR-030-L05

Cascades and orphan removal

On This Lesson 4 topics

This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.

In this lesson

choose cascade types on purpose.

Cascade passes an operation (persist, remove, ...) from parent to children.
It fits an aggregate: Order owns its OrderLines.
orphanRemoval = true deletes a child when it is removed from the parent's collection.
Do not cascade to entities with their own lifecycle: Order must not cascade to Product or Customer.
CascadeType.ALL everywhere can delete shared data by accident.

Draft outline details

java

order.removeLine(line);   // removed from the list
// at flush: delete from order_line where id = ?

Should Order cascade REMOVE to Product?

Show answer

No; products live on their own.

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