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 Post subject: How to save the child entity in unidirectional one-to-many
PostPosted: Tue Apr 04, 2017 9:08 am 
Newbie

Joined: Tue Apr 04, 2017 8:15 am
Posts: 1
Hi expert,

I am completely new in ORM world.. recently reading mapping specially one-to-many relation. but i am facing some problem to understand.

i am using this link

https://dzone.com/tutorials/java/hibern ... ons-1.html

please have a look the code.

Code:
public class Student {

  private long studentId;
private String studentName;
private Set<Phone> studentPhoneNumbers

//setter getter
}

public class Phone {

   private long phoneId;
   private String phoneType;
   private String phoneNumber;

//setter getter
}


i understand it.


Real game is here.

Code:
Set<Phone> phoneNumbers = new HashSet<Phone>();
phoneNumbers.add(new Phone("house","32354353"));
phoneNumbers.add(new Phone("mobile","9889343423"));
         
Student student = new Student("Eswar", phoneNumbers);
session.save(student);



1. why we didn't save here phoneNumbers like session.save(phoneNumbers);
2. once this above code execute then the value will be stored in both table or object(STUDENT and PHONE) right. so how will i store value in only PHONE object. or how will we implement this relation through combobox where user will select STUDENT and fill value in PHONE object not in STUDENT object. then finally save. like product/category.

3.can anyone suggest good tutorial or book where hibernate is implemented in web application. i have seen 99% tutorial explain through console or using main method.

sorry for the poor english.

thanks.


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 Post subject: Re: one to many mapping through Web
PostPosted: Tue Apr 04, 2017 10:15 am 
Hibernate Team
Hibernate Team

Joined: Thu Sep 11, 2014 2:50 am
Posts: 1227
That tutorial is wrong since it uses a @JoinTable for a one-to-many association which is not the typical way you'd map such a reationship. Check out this one which explains which is the best way to map the @OneToMany association.

As for your questions:

1. There's no such method. Usually, you want to rely on parent-side cascading. Check out this article for more info.
2. Phone is a child, and it must always point to a parent. If you use the @ManyToOne association as explained in this article, then you can achieve your goal.
3. Sure. In this tutorial, you can find more than 100 articles about Hibernate, and, if you want to get an in-depth knowledge of running your Java persistence layer at warp speed, then check out this book.

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If you liked my answer, you are going to love my High-Performance Java Persistence book and my blog as well.


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