Which JPA annotation is used to define a one-to-many relationship?

Java MCQ: Which JPA annotation is used to define a one-to-many relationship?

Answer:

Explanation:

The @OneToMany annotation is used to define a one-to-many relationship in JPA. This type of relationship indicates that one instance of an entity is associated with many instances of another entity. The @OneToMany annotation is typically used on the parent side of the relationship, where the parent entity has a collection of child entities.

Here’s an example:

@Entity
public class Department {
    @Id
    private Long id;

    @OneToMany(mappedBy = "department")
    private List<Employee> employees;

    private String name;

    // Getters and setters
}

In this example, the Department entity has a one-to-many relationship with the Employee entity, meaning that a single department can have multiple employees. The mappedBy attribute in the @OneToMany annotation indicates that the department field in the Employee entity owns the relationship.

One-to-many relationships are common in hierarchical data models and can be easily mapped in JPA using the @OneToMany annotation.

Reference links:

https://www.rameshfadatare.com/learn-java-programming/
https://www.javaguides.net/p/java-tutorial-learn-java-programming.html