Hibernate recursive many-to-many association with the same entity

by

@ManyToMany to self is rather confusing because the way you’d normally model this differs from the “Hibernate” way. Your problem is you’re missing another collection.

Think of it this way – if you’re mapping “author”https://stackoverflow.com/”book” as many-to-many, you need “authors” collection on Book and “books” collection on Author. In this case, your “User” entity represents both ends of a relationship; so you need “my friends” and “friend of” collections:

@ManyToMany
@JoinTable(name="tbl_friends",
 joinColumns=@JoinColumn(name="personId"),
 inverseJoinColumns=@JoinColumn(name="friendId")
)
private List<User> friends;

@ManyToMany
@JoinTable(name="tbl_friends",
 joinColumns=@JoinColumn(name="friendId"),
 inverseJoinColumns=@JoinColumn(name="personId")
)
private List<User> friendOf;

You can still use the same association table, but note that join / inverseJon columns are swapped on collections.

The “friends” and “friendOf” collections may or may not match (depending on whether your “friendship” is always mutual) and you don’t have to expose them this way in your API, of course, but that’s the way to map it in Hibernate.

More Related Contents:

  1. What’s the difference between JPA and Hibernate? [closed]
  2. Can someone explain mappedBy in JPA and Hibernate?
  3. Confusion: @NotNull vs. @Column(nullable = false) with JPA and Hibernate
  4. Mapping ManyToMany with composite Primary key and Annotation:
  5. When to use EntityManager.find() vs EntityManager.getReference() with JPA
  6. Could not serialize object cause of HibernateProxy
  7. @PreUpdate and @Prepersist in hibernate/JPA (using session)
  8. can someone please explain me @MapsId in hibernate?
  9. Hibernate bidirectional @ManyToOne, updating the not owning side not working
  10. Hibernate Mapping Package
  11. Hibernate, iBatis, Java EE or other Java ORM tool
  12. Hibernate/persistence without @Id
  13. mappedBy reference an unknown target entity property
  14. Mapping array with Hibernate
  15. JPA Multiple Embedded fields
  16. How does Hibernate detect dirty state of an entity object?
  17. Hibernate Criteria for Dates
  18. Java: Hibernate @OneToOne mapping
  19. Spring Data JPA: How can Query return Non- Entities Objects or List of Objects?
  20. hibernate two tables per one entity
  21. How to make a database listener with java?
  22. JPA: difference between @JoinColumn and @PrimaryKeyJoinColumn?
  23. PersistentObjectException: detached entity passed to persist thrown by JPA and Hibernate
  24. What is the solution for the N+1 issue in JPA and Hibernate?
  25. Hibernate criteria: Joining table without a mapped association
  26. what is @JoinColumn and how it is used in Hibernate
  27. How can I get the session object if I have the entity-manager?
  28. com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed
  29. How to check whether a port is open at client’s network/firewall?
  30. Array with UserType in Hibernate and PostgreSQL –> MappingException

Leave a Comment