JPA一对一使用联接表

Question

I have a room entity, a rule entity and an amenities entity. What i want to do is have the rule and the amenities entity filled manually beforehand and when i insert a room, i want depending on what rules and amenities the user chose to map the two in two join tables, room_rules and room_amenities.

How am i supposed to achieve this? When i persist a new Room Entity, should it already contain the rules and the amenities? Is it going to work if the collection of those are not mapped as cascade.persist?

Or should i 1st persist the room without them and then map them to the room?

What should i do?

UPDATE

My RoomEntity:

    public class RoomEntity {

        @Id
        @GeneratedValue(strategy= GenerationType.SEQUENCE)
        @Column(name = "id", nullable =false, unique = true)
        private Integer id;

        @Basic
        @Column(name = "title", nullable = false, length = 45)
        private String title;

        @Basic
        @Column(name = "description", nullable = false, length = 300)
        private String description;

        @Basic
        @Column(name = "square_meters", nullable = false)
        private Integer square_meters;

        @Basic
        @Column(name = "overnight_price", nullable = false)
        private double overnight_price;

        @Basic
        @Column(name = "exta_person_price", nullable = false)
        private double exta_person_price;

        @Basic
        @Column(name = "max_people", nullable = false)
        private Integer max_people;

        @Basic
        @Column(name = "min_overnights", nullable = false)
        private Integer min_overnights;

        @Basic
        @Column(name = "beds", nullable = false)
        private Integer beds;

        @Basic
        @Column(name = "bathrooms", nullable = false)
        private Integer bathrooms;

        @Basic
        @Column(name = "bedrooms", nullable = false)
        private Integer bedrooms;

        @Basic
        @Column(name = "transport", length = 300)
        private String transport;

        @Basic
        @Column(name = "neightborhood", length = 300)
        private String neightborhood;

        @Basic
        @Column(name = "house_rules", length = 200)
        private String house_rules;




        @ManyToOne(cascade = CascadeType.MERGE)
        @JoinColumn(name = "room_host", referencedColumnName = "username", /*nullable = false,*/ insertable = false, updatable = false)
        private HostEntity hostEntity;

        public HostEntity getHostEntity() {
            return hostEntity;
        }

        public void setHostEntity(HostEntity hostEntity) {
            this.hostEntity = hostEntity;
        }

        @OneToOne
        @JoinColumn(name = "room_type_id", referencedColumnName = "id", /*nullable = false,*/ insertable = false, updatable = false)
        private TypeEntity typeEntity;

        public TypeEntity getTypeEntity() {
            return typeEntity;
        }

        public void setTypeEntity(TypeEntity typeEntity) {
            this.typeEntity = typeEntity;
        }

        @OneToOne(cascade={CascadeType.ALL})
        @JoinColumn(name = "room_location", referencedColumnName = "id"/*, nullable = false, insertable = false, updatable = false*/)
        private LocationEntity locationEntity;

        public LocationEntity getLocationEntity() {
            return locationEntity;
        }

        public void setLocationEntity(LocationEntity locationEntity) {
            this.locationEntity = locationEntity;
        }


        @OneToMany(cascade = {CascadeType.ALL})
        @JoinTable(
                /*name = "room_pictures",*/
                joinColumns = {@JoinColumn(name = "room_id", referencedColumnName = "id")},
                inverseJoinColumns = {@JoinColumn (name ="picture_id", referencedColumnName = "id", unique = true)}
        )
        private Collection<PictureEntity> pictureEntities = new ArrayList<>();

        public Collection<PictureEntity> getPictureEntities() {
            return pictureEntities;
        }

        public void setPictureEntities(Collection<PictureEntity> pictureEntities) {
            this.pictureEntities = pictureEntities;
        }

        @OneToMany
        @JoinTable(
                /*name = "room_amenities",*/
                joinColumns = {@JoinColumn(name = "room_id", referencedColumnName = "id")},
                inverseJoinColumns = {@JoinColumn (name ="amenity_id", referencedColumnName = "id")}
        )
        private Collection<AmenitiesEntity> amenitiesEntities = new ArrayList<>();

        public Collection<AmenitiesEntity> getAmenitiesEntities() {
            return amenitiesEntities;
        }

        public void setAmenitiesEntities(Collection<AmenitiesEntity> amenitiesEntities) {
            this.amenitiesEntities = amenitiesEntities;
        }

         @OneToMany
         @JoinTable(
                /*name = "room_amenities",*/
                 joinColumns = {@JoinColumn(name = "room_id", referencedColumnName = "id")},
                 inverseJoinColumns = {@JoinColumn (name ="rule_id", referencedColumnName = "id")}
         )
         private Collection<RuleEntity> ruleEntities = new ArrayList<>();

        public Collection<RuleEntity> getRuleEntities() {
            return ruleEntities;
        }

        public void setRuleEntities(Collection<RuleEntity> ruleEntities) {
            this.ruleEntities = ruleEntities;
        }

 public Collection<Picture> toPicturesModel(){
        Collection<Picture> pictures = new ArrayList<>();
        for(PictureEntity o : this.pictureEntities){
            pictures.add(o.toModel());
        }
        return pictures;
    }

    public Collection<Amenities> toAmenitiesModel(){
        Collection<Amenities> amenities = new ArrayList<>();
        for(AmenitiesEntity o : this.amenitiesEntities){
            amenities.add(o.toModel());
        }
        return amenities;
    }

    public Collection<Rule> toRulesModel(){
        Collection<Rule> rules = new ArrayList<>();
        for(RuleEntity o : this.ruleEntities){
            rules.add(o.toModel());
        }
        return rules;
    }


    public Room toModel(Integer depth){
        System.out.println("RoomEntity:::toModel()");
            return new Room(
                this.hostEntity == null? null : this.hostEntity.toModel(depth),
                this.getTypeEntity() == null? null : this.typeEntity.toModel(),
                this.getLocationEntity()== null? null : this.locationEntity.toModel(),
                this.getPictureEntities() == null ? null : this.toPicturesModel(),
                this.getAmenitiesEntities() == null? null : this.toAmenitiesModel(),
                this.getRuleEntities() == null? null : this.toRulesModel(),
                this.title,  this.description,  this.square_meters,
                this.overnight_price,  this.exta_person_price,
                this.max_people,  this.min_overnights,  this.beds,  this.bathrooms,
                this.bedrooms, this.transport,  this.neightborhood, this.house_rules);
    }
}

My HostEntity inherits from RenterEntity the primary key username:

public class HostEntity extends RenterEntity {
@Basic
@Column(name = "about", length = 200)
private String about;

@Basic
@Column(name = "confirmed", nullable = false)
private boolean confirmed;

@OneToMany(cascade = CascadeType.ALL, mappedBy = "hostEntity")
private Collection<RoomEntity> roomEntities;

public Collection<RoomEntity> getRoomEntities() {
    return roomEntities;
}

public void setRoomEntities(Collection<RoomEntity> roomEntities) {
    this.roomEntities = roomEntities;

}

My LocationEntity:

public class LocationEntity{

@Id
@GeneratedValue(strategy=GenerationType.SEQUENCE)
@Column(name = "id", nullable =false, unique = true)
private Integer id;

@Basic
@Column(name = "latitude", nullable = false, precision = 0)
private double latitude;

@Basic
@Column(name = "longitude", nullable = false, precision = 0)
private double longitude;

@Basic
@Column(name = "street_number", length = STREET_MAX)
private String street_number;

@Basic
@Column(name= "route", length =  ROUTE_MAX)
private String route;

@Basic
@Column(name = "locality", length = LOCALITY_MAX)
private String locality;

@Basic
@Column(name = "postal_code", length = POSTAL_CODE_MAX)
private String postal_code;

@Basic
@Column(name = "country", length = COUNTRY_MAX)
private String country;

@Basic
@Column(name = "administrative_area_level_5", length = ADMINISTRATIVE_AREA_LEVEL_MAX)
private String administrative_area_level_5;

@Basic
@Column(name = "administrative_area_level_4", length = ADMINISTRATIVE_AREA_LEVEL_MAX)
private String administrative_area_level_4;

@Basic
@Column(name = "administrative_area_level_3", length = ADMINISTRATIVE_AREA_LEVEL_MAX)
private String administrative_area_level_3;

@Basic
@Column(name = "administrative_area_level_2", length = ADMINISTRATIVE_AREA_LEVEL_MAX)
private String administrative_area_level_2;

@Basic
@Column(name = "administrative_area_level_1", length = ADMINISTRATIVE_AREA_LEVEL_MAX)
private String administrative_area_level_1;

@Basic
@Column(name = "formatted_address", length = FORMATTED_ADRESS_MAX, nullable = false, unique = true)
private String formatted_address;

}

My TypeEntity:

public class TypeEntity {

@Id
@Column(name = "id", nullable = false, unique = true)
private Integer id;

@Basic
@Column(name = "type_name", nullable = false, length = 45)
private String type;

@OneToOne(mappedBy = "typeEntity")
private RoomEntity roomEntity;

}

My RuleEntity:

public class RuleEntity {

    @Id
    @Column(name = "id", nullable =false, unique = true)
    //@GeneratedValue(strategy= GenerationType.SEQUENCE)
    private Integer id;

    @Basic
    @Column(name = "rule", nullable =false , unique = true, length = 50)
    private String rule;
}

My PictureEntity:

public class PictureEntity {

@Id
@Column(name = "id", nullable =false, unique = true)
@GeneratedValue(strategy= GenerationType.SEQUENCE)
private Integer picture_id;

@Basic
@Column(name = "thumbnail_url", nullable =false, length = 100)
private String thumbnail_url;

@Basic
@Column(name = "medium_url", nullable =false, length = 100)
private String medium_url;

@Basic
@Column(name = "picture_url", nullable =false, length = 100)
private String picture_url;

@Basic
@Column(name = "xl_picture_url", nullable =false, length = 100)
private String xl_picture_url;
}

My AmenitiesEntity:

public class AmenitiesEntity {

@Id
@Column(name = "id", nullable =false, unique = true)
//@GeneratedValue(strategy= GenerationType.SEQUENCE)
private Integer id;

@Basic
@Column(name = "name", nullable = false, unique = true, length = 50)
private String amenity;
}

My code that creates a room is this:

public Room addRoom(RoomInput room) {
        dao.setParam("username", room.getOwner());
        List<HostEntity> owner = dao.getTuples("users.findByUsername");
        RoomEntity newRoom = new RoomEntity(room.getTitle(), room.getDescription(), room.getSquare_meters(), room.getOvernight_price(),
                room.getExta_person_price(), room.getMax_people(), room.getMin_overnights(), room.getBeds(), room.getBathrooms(),
                room.getBedrooms(), room.getTransport(), room.getNeightborhood(), room.getHouse_rules());
newRoom.setLocationEntity(room.getLocation().toEntity());
    for(Picture o :room.getPictures()){
        newRoom.getPictureEntities().add(o.toEntity());
    }
    RoomEntity entity = dao.insertTuple(newRoom);
    entity.setHostEntity(owner.get(0));
    for(Amenities o : room.getAmenities()){
        entity.getAmenitiesEntities().add(o.toEntity());
    }
    for(Rule o : room.getRules()){
        entity.getRuleEntities().add(o.toEntity());
    }
    entity.setTypeEntity(room.getType().toEntity());
    entity = dao.updateTuple(entity);
    System.out.println(entity.toString());
    return (entity == null) ? null : entity.toModel(0);
}

What happens now is that, even though my 3 join tables, room_pictures, room_rules, room_amenities get updated correctly, the room i put in the database has the foreign key of the host(username) and the type(id) null.

Is there a better way in doing all this? Right now i 1st persist the new room, and cascade persist the pictures and the location and then i merge the room with the new values of host, amenities and rules updated.

Answer 1

UPDATE I fixed the problem. Now i do one insert for the entities i want to persist with the room, aka location and pictures and one merge to connect the detatched entities amenities/rules in the join tables and host/type foreign keys in the room table. The problem with host and type was that i had in the @JoinColumn updateable and instertable to be false which was wrong. After i deleted those statements, it worked! My code in the end to persist/merge the detatched and new entities is this:

 public Room addRoom(RoomInput room) {
        dao.setParam("username", room.getOwner());
        HostEntity host = null;
        List<HostEntity> owner = dao.getTuples("users.findByUsername");
        RoomEntity newRoom = new RoomEntity(room.getTitle(), room.getDescription(), room.getSquare_meters(), room.getOvernight_price(),
                room.getExta_person_price(), room.getMax_people(), room.getMin_overnights(), room.getBeds(), room.getBathrooms(),
                room.getBedrooms(), room.getTransport(), room.getNeightborhood(), room.getHouse_rules());
        System.out.println(owner.get(0).toString());
        newRoom.setLocationEntity(room.getLocation().toEntity());
        for(Picture o :room.getPictures()){
            newRoom.getPictureEntities().add(o.toEntity());
        }
        RoomEntity entity = dao.insertTuple(newRoom);

        for(Amenities o : room.getAmenities()){
            entity.getAmenitiesEntities().add(o.toEntity());
        }
        for(Rule o : room.getRules()){
            entity.getRuleEntities().add(o.toEntity());
        }
        entity.setHostEntity(owner.get(0));
        entity.setTypeEntity(room.getType().toEntity());
        dao.updateTuple(entity);
        System.out.println(entity.toString());
        return (entity == null) ? null : entity.toModel(0);
    }