I have Department and UserRelation entity. Department entity has a departmentManager field that is tied with many to one relationship with UserRelation. The problem is i inserted the same user relation id to two different departments and now when i fetch the departments the log says More than one row with the given identifier was found: 14, for class: models.user.UserRelation

Here is the simplified version of UserRelation entity:

@NoArgsConstructor
@AllArgsConstructor
@Builder
@Getter
@Setter
@Entity
@Table(name = "user_relations")
public class UserRelation {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  @Column(name = "user_relation_id")
  private Long id;

  @OneToOne
  @JoinColumn(name = "user_id", nullable = false, unique = true)
  @JsonIgnore
  private User user;

  @OneToMany(mappedBy = "departmentManager", cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH, CascadeType.DETACH})
  @JsonIgnore
  private List<Department> departmentManagers;

}

And this is the simplified version of Department entity:

@NoArgsConstructor
@AllArgsConstructor
@Builder
@Getter
@Setter
@Entity
@Table(name = "departments")
public class Department {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  @Column(name = "department_id")
  private Long id;

  @Column(name = "department_name", nullable = false)
  private String departmentName;

  @ManyToOne
  @JoinColumn(name = "user_relation_id")
  @JsonIgnoreProperties("department")
  private UserRelation departmentManager;
}