What types of relationships exist in Hibernate?

Hibernate defines the following types of relationships between entities:

1. Basic Association: A one-to-one relationship where one entity contains a direct reference to another (without using join tables).

2. One-to-Many Associations:

   • One entity can be associated with many other entities.
   • Usually implemented using a foreign key in the "many" table.

3. Many-to-One Associations:

   • Many entities are associated with one other entity.
   • It is the inverse of the "One-to-Many" relationship.
   • Implemented with a foreign key in the "many" table.

4. One-to-One Associations:

   • Each entity of one type is associated with at most one entity of another type.
   • Implemented either through a shared primary key or a foreign key in one of the tables.

5. Many-to-Many Associations:

   • Many entities of one type are associated with many entities of another type.
   • Requires a separate join table to store the relationships.

Hibernate provides annotations to describe these relationships:

• @OneToOne
• @OneToMany
• @ManyToOne
• @ManyToMany

It is also possible to configure cascade operations for automatic propagation of operations (such as save, delete) to related entities.