CODEWITHSUNDEEP
hibernatejpaentitymanager
Mohamed Taboubi
Mohamed Taboubi

Reputation: 7021

entitymanager.find() using foreign key

May we find an entity using entitymanager using the foreign key associated to it?

For example I have a class like this : 

    @Entity
    @Table(name = "shopping_bag")
    public class ShoppingBag {

        @Id
        @GeneratedValue(generator="system-uuid")
        @GenericGenerator(name="system-uuid", strategy = "uuid")
        private String id;

        @OneToOne
        private Member member;

        @OneToMany(cascade=CascadeType.ALL, fetch = FetchType.LAZY, orphanRemoval = true)
        private Set<Product> product = new HashSet<Product>();
}

Where Member is like this : 

@Entity
@Table(name = "shopping_member")
public class Member {

    @Id
    @GeneratedValue(generator="system-uuid")
    @GenericGenerator(name="system-uuid", strategy = "uuid")
    private String id;

}

What I'm trying to do is to get all Products knowing a Member id using entityManager!

A solution is to use Native SQL - or HSQL however I want to know if there is a more simple solution ... Any Idea ?

Upvotes: 2

Views: 1822

Answers (2)

Neil Stockton
Neil Stockton

Reputation: 11531

You clearly cannot use find() since that finds an object of a type with an id (as its javadoc tells you clear enough). You can do a JPQL query to get what you want.

SELECT p FROM ShoppingBag b JOIN b.product p JOIN b.member m WHERE m.id = :memberId

Upvotes: 1

Raman Sahasi
Raman Sahasi

Reputation: 31901

You can use Hibernate Criteria

List results = entityManager.createCriteria(ShoppingBag.class, "ShoppingBag")
    .createAlias("ShoppingBag.member", "member", Criteria.LEFT_JOIN);
    .add( Restrictions.eq("member.id", someStringValue) )
    .list();

Rererence #1
Reference #2

Upvotes: 2

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