@Repository
public interface StreetInter extends JpaRepository<Street, Long> {

    Street findStreetByNameAndCity_NameAndCity_Country_Name(String street_name, String city_name, String country_name);

@Entity
@Data
public class City {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)

    private Long id;
    @NotNull
    private String name;
    @OneToMany(mappedBy = "city",cascade=CascadeType.ALL)
    private List<Street> streets;
    @ManyToOne
    @JoinColumn(name = "country_id")
    private Country country;
}


@Entity
@Data
public class Country {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)

    private Long id;

    @NotNull

    private String name;

     @OneToMany(mappedBy = "country",cascade=CascadeType.ALL)

    private List<City> cityList;
}

@Entity

@Data

public class Street {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    @NotNull
    private String name;

    @ManyToOne
    @JoinColumn(name = "city_id")
    private City city;
}