CODEWITHSUNDEEP
javahibernate
Kevin Meredith
Kevin Meredith

Reputation: 41909

Updating a One-to-Many Field in Hibernate

Let's say I have Person and Order entities in a uni-directional, one-to-many relationship.

Person

@Entity
public class Person {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Long id;

  @OneToMany(mappedBy = "person")
  Set<Order> orders = new HashSet<Order>();

  // other fields, constructor, setters and getters

}

Order

@Entity
public class Order {

  @GeneratedValue(strategy = GenerationType.AUTO)
  private Long id;

  @Column(name = "id")
  Person person;

  // other fields, constructor, setters and getters
}

How can I update a Person's Set<Order> with new Order's?

Do I need to do something like:

Order o = new Order();
// ???

person.setOrders(new HashSet<Order>(o));

Since Person has a OneToMany relationship with Order's, I'm not sure how to set a Person's orders.

Upvotes: 3

Views: 5283

Answers (2)

Shailendra
Shailendra

Reputation: 9102

Let's say I have Person and Order entities in a uni-directional, one-to-many relationship.

But your mappings suggests otherwise. It's bidirectional relationship with Order class (non-inverse side) having the responsibility of maintaining the relation.

If the relation is bidirectional with Order as non-inverse side, only setting person in Order should be sufficient to reflect the relation in database.

order.setPerson(person);

Although it is highly recommended that you set the Orders in Person as well so that your in-memory representation is consistent with the bidirectional nature of relation. Also recommended is to provide an "adder" method in Person instead of "set" which sets both ends of relationship at one place. For e.g.,

addOrders(Order order){
        this.orders.add(order);
        order.setPerson(this);
}

Also if you want to actually implement unidirectional one to many you may want to read this discussion.

Upvotes: 2

user3790568
user3790568

Reputation: 311

You can do something like this:

person1.getOrder().add(order1);

order1.setPerson(person1);

person1.getOrder().add(order2);

order2.setPerson(person1);

You can use this in loop for multiple orders

Upvotes: 1

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