JPA mappedBy引用未知目标实体属性

Question

Hello I am new to JPA Spring boot and right now I am trying to make a connection between two tables into a third one. So I have a Doctor and Patient table with it's properties, where one Doctor can examine every patient and a patient can visit every doctor.But in one examination there can be no more than one patient and one doctor. For the doctors I want to keep the information of which patients they have examined, respectively for the patients, which doctors they were examined from. I would like to create a middle table called DoctorVisit where I have the id of the doctor who did the examination and the id of the patient with some more properties like date,medicines and etc. When I try to do this I am getting an error - "mappedBy reference an unknown target entity property: /.../Patient.examinedByDoctors". If I remove the @OneToMany connection in Patient the code compiles. I would be really happy if someone can explain me where is the mistake. Thank you in advance

BaseEntity class:

@Getter
@Setter
@NoArgsConstructor
@MappedSuperclass
public class BaseEntity {

    @Id
    @GeneratedValue(strategy= GenerationType.IDENTITY)
    private long id;
}

Doctor class:

@Getter
@Setter
@NoArgsConstructor
@Entity
@Table(name="doctor")
public class Doctor extends BaseEntity{

    private String name;

    @ManyToMany(mappedBy ="doctors")
    private Set<Specialty> specialties;

    @OneToMany(mappedBy ="doctor")
    private Set<Patient> GpOfPatients;

    @OneToMany(mappedBy = "doctor")
    private List<Patient> examinedPatients;
}

Patient class:

@Getter
@Setter
@NoArgsConstructor
@Entity
@Table(name="patient")
public class Patient extends BaseEntity{

    private String name;
    private String EGN;
    private boolean insurancesPaidInLastSixMonths;

    @ManyToOne
    @JoinColumn(name="gp_id")
    private Doctor doctor;

    @OneToMany(mappedBy = "patient")
    private List<Doctor> examinedByDoctors;

}

Specialty class:

@Getter
@Setter
@NoArgsConstructor
@Entity
@Table(name="specialty")
public class Specialty extends BaseEntity{

    private String specialtyName;

    @ManyToMany
    @JoinTable(name="doctors_specialties",joinColumns = @JoinColumn(name="specialty_id"),
    inverseJoinColumns = @JoinColumn(name="doctor_id"))
    private Set<Doctor> doctors;

}

DoctorVisit class:

@Getter
@Setter
@NoArgsConstructor
@Entity
@Table(name="doctorvisit")
public class DoctorVisit extends BaseEntity {

    @ManyToOne
    @JoinColumn(name = "patient_id")
    private Patient patient;

    @ManyToOne
    @JoinColumn(name="doctor_id")
    private Doctor doctor;

    private Date date;
    private String diagonosis;

    @ManyToMany(mappedBy = "prescribedToPatients")
    private Set<Medicine> medicines;

    private int patientChart;

}

Medicine class:

@Getter
@Setter
@Entity
@Table(name = "medicine")
public class Medicine extends BaseEntity{

    private String name;
    private String manufacturer;

    @ManyToMany
    @JoinTable(name="prescribedMedicines_to_patients",joinColumns = @JoinColumn(name="medicine_id"),
            inverseJoinColumns = @JoinColumn(name="patient_id"))
    private List<Patient> prescribedToPatients;

}

Answer 1

You get this error because the Doctor class does not have a patient field. However adding a Patient won't fit your use case, because a Doctor can have multiple Patients not just one. So you have to create a ManyToMany association between Patient and Doctor or use only the DoctorVisit to connect the two entities. I would apply the second option and use special queries to get who visited who with the DISTINCT keyword for example.