JPA insert parent/child results in MySQLIntegrityConstraintViolationException

Question

This has already been asked a number of times, but I don\'t find any good answers so I\'ll ask it again.

I have parent-children unidirectional relation as follows:

Answer 1

Adding updatable=false to the parent entity solved the problem with both an insert and an updated being executed on the child table. However, I have no clue why that's the case and in fact, I don't think what I am doing is correct because it means I cannot update the child table later on if I have to.