Bidirectional Association

Rules in a Bidirectional Relationship

Bidirectional Relationships are subjected to some rules:

1. The inverse side of a bidirectional connection must use the mappedBy element of the OneToOne, OneToMany, or ManyToMany annotation to refer to its owning side. The mappedBy element specifies the property or field in the entity that is the relationship's owner.

2. Many-to-one bidirectional relationships should not define the mappedBy element on the many sides. The relationship's many sides are always the owning side.

3. The owning side corresponds to the side that contains the appropriate foreign key in one-to-one bidirectional relationships.

4. In the case of many-to-many bidirectional relationships, either of the sides can be the owner.

Bidirectional vs Unidirectional Association

A bidirectional association allows navigational access in both directions, allowing you to visit the other side without making explicit queries. It enables you to use cascading options in both directions. There is an owning side and an inverse side to every bidirectional interaction. 

On the other hand, a unidirectional association has just one side that owns. The owner of a relationship controls how the Persistence runtime changes the relationship in the database.

You can also check out Has-A Relationship in Java here.

Frequently Asked Questions

Describe the layout of Hibernate Architecture?

Hibernate offers a layered architecture that allows users to work without knowing the underlying APIs. Hibernate uses the database and configuration data to offer the application with persistence services (and persistent objects).

Is Session thread safe in Hibernate?

No, Session object is not thread-safe in Hibernate and intended to be used with-in single thread in the application.

What is lazy loading in Hibernate Architecture?

The Lazy setting determines whether child items are loaded while the Parent Object is loaded. You must achieve this by modifying the parent class's hibernate mapping file. Lazy = True (means not to load child) The sluggish loading of child objects is enabled by default.

Conclusion

This blog discussed the bidirectional association in classes within hibernate and its differences from the unidirectional association.

If you want to explore more blogs on this topic, please follow these blogs especially curated for readers like you - JDBC, JDBC Connection, Guide to ORM, Spring Boot JDBC.

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