Hibernate update one child in one to many

Question

I'm new to hibernate so I don't understand some basic things. I have Entity A and B. And it's a one to many relationship. So A can have multiple B's. Below is code to save when adding a new B to A. That's working.

    A a= this.aService.getAById(AID);
    b.setA(a);
    a.getBSet().add(b);
    this.aService.saveA(a);

But how can I edit one B entity? Do I first have to remove the B entity that I want to edit from the Set? Really sorry if it's an obvious question. But I already searched with Google and the only examples I can find is when you make new entities and not edit.

score 0 · Answer 1 · answered Oct 31 '17 at 12:21

0

You need to first get B from the database.

B b = this.bService.getBById(BID);
...
//update b
this.bService.updateB(b);

answered Oct 31 '17 at 12:21

Abdullah Khan

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So retrieve B that I want to edit. update B and that's it? Don't i have to edit the set that A which contains the B that I want to edit? – Urban Oct 31 '17 at 12:24
You might as well want to upvote and accept this answer so that it could be of help to others ;) – Abdullah Khan Nov 02 '17 at 08:30

score -1 · Answer 2 · edited Oct 31 '17 at 19:25

-1

//Whether you want update entity B:
Public void updateBEntity(Integer idB) {
 B b = session.get(B.class, idB);
//For edit you only have to use the set's methods:
b.setName(anything);
b.setPosition(2);
//final y, that's all
session.merge(b);
} 
//In your class controller or Action

More information about merge/persist:

What is the difference between persist() and merge() in Hibernate?

edited Oct 31 '17 at 19:25

SiHa

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answered Oct 31 '17 at 14:13

peterzinho16

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Hibernate update one child in one to many

2 Answers2