Java Persistence API

Entity Relationships

One-to-One

One-to-One Example

One-to-Many

One-to-Many Example

  @Entity
  public class Department {
    ...
    @OneToMany(mappedBy="department") // Employee is the "owner"
    public Set<Employee> getEmployees() {
        return employees;
    }
    ...
  }

  @Entity
  public class Employee {
    ...
    @ManyToOne
    public Department getDepartment() {
        return department;
    }
    ...
  }

Many-to-Many

Many-to-Many Example