I'm using spring boot to construct a database using AWS RDS as well. I want to track down how many stars a user gives to different products. I learnt to go around the many-to-many relationship by creating a table connecting two one-to-many other tables. For this reason, I have created the following tables:
When a user rates a product, an api is called through the put command in order to track down which user(uid) rates which product(pid). When the product(pid) is not rated by anyone, a rate_item is created that contains the pid and also the uid. However, when another user (with a different uid) rates the same product (same pid), the rate_item is updated, which is a problem becausse supposedly, a new row containing the same pid and a different uid should be created, as seen in the following (user with "uid 1" has already rated the same product and when user with "uid 2" rates the same product, the entity gets updated, but not like a new entity is created):
ProductEntity:
#Entity
#Table(name = "product")
public class ProductEntity {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Column(name = "pid",nullable = false)
private Integer pid;
#Column(name = "name", nullable = false)
private String name;
#Column(name="theme", nullable = false)
private String theme;
#Column(name="color", nullable = false)
private String color;
#Column(name="sizeZero", nullable = true)
private String sizeZero;
#Column(name="sizeOne", nullable = true)
private String sizeOne;
#Column(name="sizeTwo", nullable = true)
private String sizeTwo;
#Column(name="sizeThree", nullable = true)
private String sizeThree;
#Column(name="description",nullable = false)
private String description;
#Column(name = "image_url", nullable = false)
private String imageUrl;
#Column(name = "price",nullable = false)
private BigDecimal price;
#Column(name = "stock",nullable = false)
private Integer stock;
public ProductEntity(CreateProductData createProductData) {
this.pid = createProductData.getPid();
this.name = createProductData.getName();
this.theme =createProductData.getTheme();
this.color=createProductData.getColor();
this.sizeZero=createProductData.getSizeZero();
this.sizeOne =createProductData.getSizeOne();
this.sizeTwo =createProductData.getSizeTwo();
this.sizeThree =createProductData.getSizeThree();
this.description =createProductData.getDescription();
this.imageUrl = createProductData.getImageUrl();
this.price = createProductData.getPrice();
this.stock = createProductData.getStock();
}
public ProductEntity(){
}
public Integer getPid() {
return pid;
}
public void setPid(Integer pid) {
this.pid = pid;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getTheme() {
return theme;
}
public void setTheme(String productType) {
this.theme = productType;
}
public String getColor() {
return color;
}
public void setColor(String color) {
this.color = color;
}
public String getSizeZero() {
return sizeZero;
}
public void setSizeZero(String sizeZero) {
this.sizeZero = sizeZero;
}
public String getSizeOne() {
return sizeOne;
}
public void setSizeOne(String smallSize) {
this.sizeOne = smallSize;
}
public String getSizeTwo() {
return sizeTwo;
}
public void setSizeTwo(String mediumSize) {
this.sizeTwo = mediumSize;
}
public String getSizeThree() {
return sizeThree;
}
public void setSizeThree(String largeSize) {
this.sizeThree = largeSize;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getImageUrl() {
return imageUrl;
}
public void setImageUrl(String imageUrl) {
this.imageUrl = imageUrl;
}
public BigDecimal getPrice() {
return price;
}
public void setPrice(BigDecimal price) {
this.price = price;
}
public Integer getStock() {
return stock;
}
public void setStock(Integer stock) {
this.stock = stock;
}
}
UserEntity:
#Entity
#Table(name="User")
public class UserEntity {
#Id
#GeneratedValue(strategy=GenerationType.IDENTITY)
#Column(name="uid",nullable = false)
private Integer uid;
#Column(name="username", nullable = false)
private String username;
#Column(name="email", nullable = false, unique = true)
private String email;
#Column(name="password", nullable = false)
private String password;
#Column(name = "firebase_uid", nullable = false)
private String firebaseUid;
#Column(name= "emailVerified", nullable = false,columnDefinition = "boolean default false")
private Boolean emailVerified=false;
#Column(name="subscribed", nullable = false)
private Boolean subscribed;
public UserEntity(UserEntity tempUserEntity){
this.uid=tempUserEntity.getUid();
this.firebaseUid=tempUserEntity.getFirebaseUid();
this.email=tempUserEntity.getEmail();
}
public UserEntity(CreateFirebaseUserData createFirebaseUserData){
this.username=createFirebaseUserData.getUsername();
this.email=createFirebaseUserData.getEmail();
this.password=createFirebaseUserData.getPassword();
this.firebaseUid= createFirebaseUserData.getFirebaseUid();
this.subscribed=createFirebaseUserData.getSubscribed();
}
public UserEntity(){
}
public Integer getUid() {
return uid;
}
public void setUid(Integer uid) {
this.uid = uid;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public String getFirebaseUid() {
return firebaseUid;
}
public void setFirebaseUid(String firebaseUid) {
this.firebaseUid = firebaseUid;
}
public Boolean getEmailVerified() {
return emailVerified;
}
public void setEmailVerified(Boolean emailVerified) {
this.emailVerified = emailVerified;
}
public Boolean getSubscribed() {
return subscribed;
}
public void setSubscribed(Boolean subscribed) {
this.subscribed = subscribed;
}
}
RatingEntity:
#Entity
#Table(name="Rating")
public class ProductsRatedByUserEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name="pruid")
private Integer pruid;
#OneToOne
#JoinColumn(name="pid",nullable = false)
private ProductEntity product;
#ManyToOne
#JoinColumn(name="uid",nullable = false)
private UserEntity user;
#Column
private Integer starsGiven;
#Column(name="total_stars", nullable = false)
private Integer totalStars;
#Column(name="total_num_of_users_who_rated", nullable = false)
private Integer totalNumOfUsersWhoRated;
#Column(name="average_stars")
private BigDecimal averageStars;
public ProductsRatedByUserEntity(UserEntity userEntity, ProductEntity productEntity, Integer numOfStars){
this.product=productEntity;
this.user=userEntity;
this.starsGiven=numOfStars;
this.totalStars=numOfStars;
this.totalNumOfUsersWhoRated=1;
this.averageStars=BigDecimal.valueOf(this.getTotalStars()).divide(BigDecimal.valueOf(this.getTotalNumOfUsersWhoRated()));
}
public ProductsRatedByUserEntity(ProductEntity product,UserEntity user,Integer numOfStars,Integer newTotalNumOfStars, Integer newTotalNumberOfUsers, BigDecimal averageStars){
this.product=product;
this.user=user;
this.starsGiven=numOfStars;
this.totalStars=newTotalNumOfStars;
this.totalNumOfUsersWhoRated=newTotalNumberOfUsers;
this.averageStars=averageStars;
}
public ProductsRatedByUserEntity(){
}
public Integer getPruid() {
return pruid;
}
public void setPruid(Integer plbuid) {
this.pruid = plbuid;
}
public ProductEntity getProduct() {
return product;
}
public void setProduct(ProductEntity product) {
this.product = product;
}
public UserEntity getUser() {
return user;
}
public void setUser(UserEntity user) {
this.user = user;
}
public Integer getStarsGiven() {
return starsGiven;
}
public void setStarsGiven(Integer starsGiven) {
this.starsGiven = starsGiven;
}
public Integer getTotalStars() {
return totalStars;
}
public void setTotalStars(Integer totalStars) {
this.totalStars = totalStars;
}
public Integer getTotalNumOfUsersWhoRated() {
return totalNumOfUsersWhoRated;
}
public void setTotalNumOfUsersWhoRated(Integer totalNumOfUsersWhoLiked) {
this.totalNumOfUsersWhoRated = totalNumOfUsersWhoLiked;
}
public BigDecimal getAverageStars() {
return averageStars;
}
public void setAverageStars(BigDecimal averageStars) {
this.averageStars = averageStars;
}
}
Api:
#CrossOrigin
#RestController
public class ProductApi {
private ProductService productService;
private ProductsRatedByUserService productsRatedByUserService;
#Autowired
public ProductApi(ProductService productService,ProductsRatedByUserService productsRatedByUserService){
this.productService=productService;
this.productsRatedByUserService=productsRatedByUserService;
}
#PutMapping("/product/rating/{pid}/{numOfStars}")
public ProductsRatedByUserResponseDto updateRating(#PathVariable Integer pid, #PathVariable Integer numOfStars, JwtAuthenticationToken jwtAuthenticationToken) throws ProductFoundByIdException {
FirebaseUserData firebaseUserData=new FirebaseUserData(jwtAuthenticationToken);
ProductsRatedByUserDetail productsRatedByUserDetail=productsRatedByUserService.updateProductRating(pid,numOfStars,firebaseUserData);
return new ProductsRatedByUserResponseDto(productsRatedByUserDetail);
}
}
RatingServiceImpl:
#Service
#Component
public class ProductsRatedByUserServiceImpl implements ProductsRatedByUserService {
public ProductsRatedByUserRepository productsRatedByUserRepository;
public ProductRepository productRepository;
public UserRepository userRepository;
#Autowired
public ProductsRatedByUserServiceImpl(ProductsRatedByUserRepository productsRatedByUserRepository,ProductRepository productRepository,UserRepository userRepository){
this.productsRatedByUserRepository=productsRatedByUserRepository;
this.productRepository=productRepository;
this.userRepository=userRepository;
}
#Override
public ProductsRatedByUserDetail updateProductRating(Integer pid, Integer numOfStars, FirebaseUserData firebaseUserData) throws ProductFoundByIdException {
if(!productRepository.existsById(pid)){
throw new ProductFoundByIdException();
}
UserEntity userEntity=userRepository.findUserEntityByEmail(firebaseUserData.getEmail());
ProductEntity productEntity =productRepository.findById(pid).orElse(null);
//check if the product has been rated by *any user*
//If no, we need to create an entity
if(!productsRatedByUserRepository.existsByProduct(productEntity)){
ProductsRatedByUserEntity productsRatedByUserEntity=new ProductsRatedByUserEntity(userEntity, productEntity, numOfStars);
ProductsRatedByUserEntity productsRatedByUserEntityReturned=productsRatedByUserRepository.save(productsRatedByUserEntity);
System.out.println("the product has been rated by *any user*");
return new ProductsRatedByUserDetail(productsRatedByUserEntityReturned);
}
//If yes, we update the entity from there
else {
//if the product has been rated by this very user
if (productsRatedByUserRepository.existsByUserAndProduct(userEntity, productEntity)) {
ProductsRatedByUserEntity productsRatedByUserEntity = productsRatedByUserRepository.findTopByUserAndProduct(userEntity, productEntity);
productsRatedByUserEntity.setTotalStars(productsRatedByUserEntity.getTotalStars() - productsRatedByUserEntity.getStarsGiven() + numOfStars);
productsRatedByUserEntity.setStarsGiven(numOfStars);
productsRatedByUserEntity.setAverageStars(BigDecimal.valueOf(productsRatedByUserEntity.getTotalStars()).divide(BigDecimal.valueOf(productsRatedByUserEntity.getTotalNumOfUsersWhoRated())));
ProductsRatedByUserEntity productsRatedByUserEntityReturned = productsRatedByUserRepository.save(productsRatedByUserEntity);
System.out.println("the product has been rated by this very user");
return new ProductsRatedByUserDetail(productsRatedByUserEntityReturned);
} else {
//The product has not been rated by this very user
ProductsRatedByUserEntity productsRatedByUserEntity = productsRatedByUserRepository.findTopByProduct(productEntity);
int newTotalNumOfStars = (productsRatedByUserEntity.getTotalStars() + numOfStars);
int newTotalNumberOfUsers = productsRatedByUserEntity.getTotalNumOfUsersWhoRated() + 1;
productsRatedByUserEntity.setUser(userEntity);
System.out.println("The product has not been rated by this very user");
return new ProductsRatedByUserDetail(productsRatedByUserRepository.save(new ProductsRatedByUserEntity(productEntity, userEntity, numOfStars, newTotalNumOfStars, newTotalNumberOfUsers, BigDecimal.valueOf(newTotalNumOfStars).divide(BigDecimal.valueOf(newTotalNumberOfUsers)))));
}
}
}
}
RatingServiceInterface:
public interface ProductsRatedByUserService {
ProductsRatedByUserDetail updateProductRating(Integer pid, Integer numOfStars, FirebaseUserData firebaseUserData) throws ProductFoundByIdException;
}
Repository:
public interface ProductsRatedByUserRepository extends CrudRepository<ProductsRatedByUserEntity,Integer> {
boolean existsByProduct(ProductEntity product);
ProductsRatedByUserEntity findTopByProduct(ProductEntity product);
boolean existsByUserAndProduct(UserEntity userEntity, ProductEntity product);
ProductsRatedByUserEntity findTopByUserAndProduct(UserEntity userEntity, ProductEntity product);
}
I will really appreciate anyone who can help me with this! I've been stuck for a whole day! I don't want to use the many-to-many annotation because it seems a bit messy. Thanks!
I have found the mistake. In my RatingEntity code, the getter and setter are erroneous. There's some typos there. It should be
public Integer getPruid() {
return pruid;
}
public void setPruid(Integer pruid) {
this.pruid = pruid;
}
I'm working on Calorie Counter Application. After logging in, each user will only have access to their meals.
I have a database like below:
I'll display all information like the template below.
Meal 1
Chicken breast
100g
130kcal
Apple
200g
100kcal
Tomatoes
300g
30kcal
Meal 2
Chicken breast
100g
130kcal
Apple
200g
100kcal
Tomatoes
300g
30kcal
User class:
#Entity
#Table(name = "users")
public class User {
private int id;
private String username;
private String password;
private int age;
private String email;
private Gender gender;
private List<Meal> meals;
public User() {
}
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
#Column(name = "username")
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
#Column(name = "password")
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
#Column(name = "age")
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
#Column(name = "email")
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
#Column(name = "gender")
public Gender getGender() {
return gender;
}
public void setGender(Gender gender) {
this.gender = gender;
}
#OneToMany(mappedBy = "user")
public List<Meal> getMeals() {
return meals;
}
public void setMeals(List<Meal> meals) {
this.meals = meals;
}
private enum Gender{
MALE,
FEMALE
}
}
Meal class:
#Entity
#Table(name = "meals")
public class Meal {
private int id;
private LocalDate date = LocalDate.now();
private User user;
private List<MealFoodProduct> mealFoodProducts;
public Meal() {
}
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
#OneToMany(mappedBy = "foodProduct")
public List<MealFoodProduct> getMealFoodProducts() {
return mealFoodProducts;
}
public void setMealFoodProducts(List<MealFoodProduct> mealFoodProducts) {
this.mealFoodProducts = mealFoodProducts;
}
#Column(name = "created_at")
public LocalDate getDate() {
return date;
}
public void setDate(LocalDate date) {
this.date = date;
}
#ManyToOne
#JoinColumn(name = "user_id")
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
}
FoodProduct class:
#Entity
#Table(name = "food_products")
public class FoodProduct {
private int id;
private String productName;
private Double proteins;
private Double fats;
private Double carbohydrates;
private Double calories;
public FoodProduct() {
}
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
#Column(name = "product_name")
public String getProductName() {
return productName;
}
public void setProductName(String productName) {
this.productName = productName;
}
#Column(name = "proteins")
public Double getProteins() {
return proteins;
}
public void setProteins(Double proteins) {
this.proteins = proteins;
}
#Column(name = "fats")
public Double getFats() {
return fats;
}
public void setFats(Double fats) {
this.fats = fats;
}
#Column(name = "carbohydrates")
public Double getCarbohydrates() {
return carbohydrates;
}
public void setCarbohydrates(Double carbohydrates) {
this.carbohydrates = carbohydrates;
}
#Override
public String toString() {
return productName;
}
#Column(name = "calories")
public Double getCalories() {
return calories;
}
public void setCalories(Double calories) {
this.calories = calories;
}
}
MealFoodProcuct class
#Entity
#Table(name = "meals_food_products")
public class MealFoodProduct {
private Meal meal;
private FoodProduct foodProduct;
private double weight;
public MealFoodProduct() {
}
#ManyToOne
#JoinColumn(name = "meal_id")
public Meal getMeal() {
return meal;
}
public void setMeal(Meal meal) {
this.meal = meal;
}
#ManyToOne
#JoinColumn(name = "food_product_id")
public FoodProduct getFoodProduct() {
return foodProduct;
}
public void setFoodProduct(FoodProduct foodProduct) {
this.foodProduct = foodProduct;
}
#Column(name = "food_product_weight")
public double getWeight() {
return weight;
}
public void setWeight(double weight) {
this.weight = weight;
}
}
My questions:
Is it correct way to connect these classes?
What should be an ID in MealFoodProduct class?
I would suggest you to use composite identifiers with #IdClass for the MealFoodProduct entity.
#Entity
#Table(name = "meals_food_products")
#IdClass( MealFoodProductPK.class )
public class MealFoodProduct {
#Id
#ManyToOne
#JoinColumn(name = "meal_id")
public Meal getMeal() {
return meal;
}
#Id
#ManyToOne
#JoinColumn(name = "food_product_id")
public FoodProduct getFoodProduct() {
return foodProduct;
}
// ...
}
public class MealFoodProductPK implements Serializable {
private Meal meal;
private FoodProduct foodProduct;
public MealFoodProductPK(Meal meal, FoodProduct foodProduct) {
this.meal = meal;
this.foodProduct = foodProduct;
}
public MealFoodProductPK() {
}
//Getters, setters, equals, hashCode are omitted for brevity
}
Additional details see here.
P.S. Other parts of your mapping look good.
I am trying to fetch list of train entities using source and destination properties of route entity which has one to many relationship with each other. The train table having route id as foreign key. The table names are route and train respectively. Please help me as the query is throwing java.lang.IllegalArgumentException: Validation failed for query for method public abstract java.util.List com.infyrail.app.repository.RouteRepository.findBySourceDestination(java.lang.String,java.lang.String)!
RouteRepository:
public interface RouteRepository extends JpaRepository<RouteEntity, Integer> {
#Query("SELECT t FROM train t JOIN route r WHERE r.source=?1 AND r.destination=?2")
public List<TrainEntity> findBySourceDestination(String source,String destination);
}
RouteEntity:
#Entity
#Table(name="route")
public class RouteEntity {
#Id
#GenericGenerator(name="route_id",
strategy="com.infyrail.app.generator.RouteIdGenerator")
#GeneratedValue(generator = "route_id")
#Min(value = 100)
#Max(value = 999)
Integer id;
String source;
String destination;
#OneToMany(mappedBy = "route",
cascade=CascadeType.ALL,orphanRemoval = true)
private List<TrainEntity> trainList;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getSource() {
return source;
}
public void setSource(String source) {
this.source = source;
}
public String getDestination() {
return destination;
}
public void setDestination(String destination) {
this.destination = destination;
}
public List<TrainEntity> getTrainList() {
return trainList;
}
public void setTrainList(List<TrainEntity> trainList) {
this.trainList = trainList;
}
}
TrainEntity:
#Entity
#Table(name="train")
public class TrainEntity {
//#GeneratedValue(strategy = GenerationType.IDENTITY)
#Id
#GenericGenerator(name="train_id",
strategy="com.infyrail.app.generator.TrainIdGenerator")
#GeneratedValue(generator = "train_id")
#Min(value = 100)
#Max(value = 999)
Integer id;
String trainName;
String arrivalTime;
String departureTime;
Double fare;
#ManyToOne(fetch = FetchType.LAZY)
#Autowired
RouteEntity route;
public RouteEntity getRoute() {
return route;
}
public void setRoute(RouteEntity route) {
this.route = route;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getTrainName() {
return trainName;
}
public void setTrainName(String trainName) {
this.trainName = trainName;
}
public String getArrivalTime() {
return arrivalTime;
}
public void setArrivalTime(String arrivalTime) {
this.arrivalTime = arrivalTime;
}
public String getDepartureTime() {
return departureTime;
}
public void setDepartureTime(String departureTime) {
this.departureTime = departureTime;
}
public Double getFare() {
return fare;
}
public void setFare(Double fare) {
this.fare = fare;
}
}
Here is the problem. Your query should define the table bean name instead of the actual table name.
In your case you should use TrainEntity instead of train and RouteEntity instead of route.
public interface RouteRepository extends JpaRepository<RouteEntity, Integer> {
#Query("SELECT t FROM TrainEntity t JOIN RouteEntity r WHERE r.source=?1 AND r.destination=?2")
public List<TrainEntity> findBySourceDestination(String source,String destination);
}
The first time I implemented the findByContentContaining function in the repository everyting worked fine. But now when I call the function and if it finds something, it gives me an error. If it doesn't find anything it returns an empty list.
This is my repository (everyting works except the findByContentContaining function):
public interface KweetRepo extends CrudRepository<Kweet, Integer> {
Kweet getById(Integer id);
List<Kweet> findTop10ByPosterId(int id);
List<Kweet> findByContentContaining(String content);
List<Kweet> findByPosterId(int id);
}
This is the model for my Kweet class
#Entity
public class Kweet implements Comparable<Kweet>{
#Id
#GeneratedValue
private int id;
#Column(name="content")
private String content;
#JsonFormat(shape = JsonFormat.Shape.STRING)
private Date dateTime;
#ManyToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
#JoinColumn(name = "user_id")
private User poster;
#OneToMany(cascade = CascadeType.ALL)
#JoinTable(name="KweetLikedBy")
private List<User> likedBy;
public Kweet() {
}
public Kweet(String content, Date dateTime, User poster, List<User> likedBy) {
this.content = content;
this.dateTime = dateTime;
this.poster = poster;
this.likedBy = likedBy;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
public Date getDateTime() {
return dateTime;
}
public void setDateTime(Date dateTime) {
this.dateTime = dateTime;
}
public int getPoster() {
return poster.getId();
}
public void setPoster(User poster) {
this.poster = poster;
}
public List<User> getLikedBy() {
return likedBy;
}
public void addLikedBy(User user) {
this.likedBy.add(user);
}
public void removeLikedBy(User user) {
this.likedBy.remove(user);
}
#Override
public int compareTo(Kweet o) {
return getDateTime().compareTo(o.getDateTime());
}
}
These are my model classes:
Film.java
#Entity
public class Film {
private Integer id;
private String title;
private List<FilmActor> filmActors;
#OneToMany(mappedBy = "film")
public List<FilmActor> getFilmActors() {
return filmActors;
}
public void setFilmActors(List<FilmActor> filmActors) {
this.filmActors = filmActors;
}
}
Actor.java
#Entity
public class Actor {
private Integer id;
private String firstname;
private String lastname;
private List<FilmActor> filmActors;
#OneToMany(mappedBy = "actor")
public List<FilmActor> getFilmActors() {
return filmActors;
}
public void setFilmActors(List<FilmActor> filmActors) {
this.filmActors = filmActors;
}
}
And this is the Join Table Entity:
#Entity
#Table(name = "film_actor")
public class FilmActor {
private FilmActorPK id;
private Film film;
private Actor actor;
private Timestamp lastUpdate;
#EmbeddedId
public FilmActorPK getId() {
return id;
}
public void setId(FilmActorPK id) {
this.id = id;
}
#ManyToOne
#MapsId("film")
#JoinColumn(name = "film_id")
public Film getFilm() {
return film;
}
public void setFilm(Film film) {
this.film = film;
}
#ManyToOne
#MapsId("actor")
#JoinColumn(name = "actor_id")
public Actor getActor() {
return actor;
}
public void setActor(Actor actor) {
this.actor = actor;
}
#Column(name = "last_update")
public Timestamp getLastUpdate() {
return lastUpdate;
}
public void setLastUpdate(Timestamp lastUpdate) {
this.lastUpdate = lastUpdate;
}
}
and the Primary Key class:
#Embeddable
public class FilmActorPK implements Serializable {
private int actorId;
private int filmId;
#Column(name = "actor_id")
public int getActorId() {
return actorId;
}
public void setActorId(int actorId) {
this.actorId = actorId;
}
#Column(name = "film_id")
public int getFilmId() {
return filmId;
}
public void setFilmId(int filmId) {
this.filmId = filmId;
}
}
So I want to find films where 2 given actors acts. This is what I have:
#Override
public Collection<Film> filmsActorsTogether(Actor a, Actor b) {
final List<Film> filmsOfActorA = filmsOfActor(a);
final List<Film> filmsOfActorB = filmsOfActor(b);
final Collection<Film> intersection = CollectionUtils.intersection(filmsOfActorA, filmsOfActorB);
return intersection;
}
#Override
public List<Film> filmsOfActor(Actor actor) {
final EntityManager entityManager = persistenceUtil.getEntityManager();
final Actor persistentActor = entityManager.find(Actor.class, actor.getId());
final ArrayList<Film> films = new ArrayList<Film>();
for (FilmActor filmActor : persistentActor.getFilmActors()) {
films.add(filmActor.getFilm());
}
entityManager.close();
return films;
}
Is there any way to achieve this without fetching ALL films of 2 actors, and using filtering in memory? How do I get the Films directly from the DB with JQL?
Maybe there is something more elegant, but the following query should work:
select f from Film f where
(select count(fa.id) from FilmActor fa
where fa.film = f
and (fa.actor = :actor1 or fa.actor = :actor2)) = 2
Side note: your PK class should have a correct equals() and hashCode() methods