I had entities User, BlockUnit, Block and Unit as Follows.
User has ManyToMany relation with blockunit.
#Entity
public class User {
#ManyToMany
private Set<BlockUnit> blockUnits;
}
#Entity
public class BlockUnit {
#Id
private Long id;
#OneToOne(targetEntity = Block.class)
#JoinColumn(name = "block_id")
private Block block;
#OneToOne(targetEntity = Unit.class)
#JoinColumn(name = "unit_id")
private Unit unit;
#ManyToMany(fetch = FetchType.LAZY)
private Set<User> users = new HashSet<>();
}
BlockUnit has OneToOne relation with Block and Unit.
#Entity
public class Block {
#Id
private Long id;
}
#Entity
public class Unit {
#Id
private Long id;
}
How should I create the JPA criteria specification for above in order to select user's having Block ID and Unit ID?
Thank you very much in advance!
Related
User.java
#Entity
#Table(name = "users")
public class User implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "user_role_id", referencedColumnName = "id")
private UserRole userRole;
}
UserRole.java
#Data
#Entity
#Table(name = "user_roles")
public class UserRole implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
}
Client.java
#Data
#Entity
#Table(name = "clients")
public class Client implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumns({ #JoinColumn(name = "user_id", referencedColumnName = "id"),
#JoinColumn(name = "user_role_id", referencedColumnName = "user_role_id") })
private User user;
}
Error
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.MappingException: Unable to find column with logical name: user_role_id in users
In RDBMS, users.(id, user_role_id) is unique so clients table can refer to that.
Last time, I was using insertable = false, updatable = false on user_role_id, but when I want to add records of new client, I always need to add user_role_id manually user.setUserRoleId(userRole.getId()) after user.setUserRole(userRole) and I think that is bad practice of ORM (it should be added automatically when I set user.setUserRole(userRole))
#Column(name = "user_role_id", insertable = false, updatable = false)
private Integer userRoleId;
What should I do so the relation can be mapped in Spring JPA? and what is the best practice?
In other words, this is also mean how to reference to foreign key generated logical name column?
OK! Please try following configuration:
Below is a important code part and under this link you may find repository with working example
UserRole.java
#Data
#Entity
#Table(name = "user_roles")
public class UserRole implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "role_id")
private Integer roleId;
}
User.java
#Data
#Entity
#Table(name = "users")
public class User implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "user_id")
private Integer userId;
#ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name = "user_role_id", referencedColumnName = "role_id")
private UserRole userRole;
}
Client.java
#Data
#Entity
#Table(name = "clients")
public class Client implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "client_id")
private Integer clientId;
#OneToOne(fetch = FetchType.LAZY)
#JoinColumns(
value = {
#JoinColumn(name = "client_role_id", referencedColumnName = "user_role_id"),
#JoinColumn(name = "client_user_id", referencedColumnName = "user_id"),
}
,
foreignKey = #ForeignKey(
name = "FK_user_with_role",
foreignKeyDefinition = "FOREIGN KEY (client_user_id, client_role_id)\n" +
" REFERENCES users \n" +
" (user_id, user_role_id) \n" +
" ON UPDATE CASCADE\n" +
" ON DELETE CASCADE")
)
private User user;
}
Please note that beside adding a foreignKey in the Client implementation, you MUST keep the sequence of #JoinColum annotations.. I don't know what is the reason behind, but if you flip those lines you'll still get your error as it was before :)
EDIT: I've added another answer which fits best in my opinion. I'm leaving this one as well to see the other steps I tried.
Though the solution is not elegant and not using JPA as requested. Just in case anything in here would be helpful
If I understand the main issue correctly - you want to bind Client entity with Role entity via User entity, by first setting User's Role and then transfer that "property" by using only UserId instead setting additionally RoleId while creating Client.
Basically after playing for a while with your model I think the main issue is to assign data to each other within a #Transactional methods. That seems to be caused ba Lazy fetch strategy.
My proposal for solution that binds all your Entities according expectations differs only from yours with ommiting the RoleId JoinColumn in Clients table. I have checked that when calling a service that would have #Transactional methods, you can assign a Role to the User and User to the Client with simple user.setRole(roleEntity) followed by client.setUser(userEntity).
All the data is then consistent. No need to call further like getters and setters as you mentioned in the second part of your question. Question is if for any reason you need to have RoleId as well in your Clients Table, then this soultion would have to be enhanced by additional column?
UserRole.java
#Entity
#Table(name = "user_roles")
public class UserRole implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "role_id")
private Integer roleId;
//getters and setters and toString
}
User.java
#Entity
#Table(name = "users")
public class User implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "user_id")
private Integer userId;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "user_role_id", referencedColumnName = "role_id")
private UserRole userRole;;
//getters and setters and toString;
}
Client.java
#Entity
#Table(name = "clients")
public class Client implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "client_id")
private Integer clientId;
#OneToOne(fetch = FetchType.LAZY)
#JoinColumns({
#JoinColumn(name = "client_user_id", referencedColumnName = "user_id"),
})
private User user;
#Column(name = "client_role_id")
private Integer roleId;
#PrePersist
#PreUpdate
private void prePersist(){
try {
roleId = getUser().getUserRole().getRoleId();
} catch (NullPointerException e){
roleId = null;
}
}
//getters and setters and toString
}
UserService.java
#Service
public class UserService {
UserRepo userRepo;
public UserService(UserRepo userRepo) {
this.userRepo = userRepo;
}
#Transactional
public void save(User user) {
userRepo.save(user);
}
#Transactional
public User getReferenceById(int i) {
return userRepo.getReferenceById(i);
}
}
ClientService.java
#Service
public class ClientService {
private ClientRepo clientRepo;
private UserService userService;
public ClientService(ClientRepo clientRepo, UserService userService) {
this.clientRepo = clientRepo;
this.userService = userService;
}
#Transactional
public Client save(Client client){
return clientRepo.save(client);
}
#Transactional
public Client getReferenceById(int i) {
return clientRepo.getReferenceById(i);
}
#Transactional
public void printClient(Client client){
client = clientRepo.getReferenceById(client.getClientId());
System.out.println(client);
}
#Transactional
public void bindUserToClient(int userId, int clientId) {
Client entity = clientRepo.findById(clientId).orElseGet(Client::new);
entity.setUser(userService.getReferenceById(userId));
}
#Transactional
public void printClient(int i) {
clientRepo.findById(i).ifPresentOrElse(this::printClient, EntityNotFoundException::new);
}
}
This configuration after running this commandLineRunner:
#Configuration
public class Config {
#Bean
#Transactional
public CommandLineRunner commandLineRunner(
#Autowired UserRoleRepo roleRepo,
#Autowired UserService userService,
#Autowired ClientService clientService
) {
return args -> {
for (int i = 0; i < 5; i++) {
roleRepo.save(new UserRole());
}
for (int i = 5; i > 0; i--) {
User user = new User();
user.setUserRole(roleRepo.getReferenceById(i));
userService.save(user);
}
Client client = new Client();
client.setUser(userService.getReferenceById(2));
client = clientService.save(client);
clientService.printClient(client);
client = new Client();
client.setClientId(1);
clientService.printClient(client);
int userId = 5;
clientService.bindUserToClient(userId, 1);
clientService.printClient(1);
};
}
}
gave me correct output in the console:
Client{id=1, user=User{id=2, userRole=UserRole{id=4}}}
Client{id=1, user=User{id=2, userRole=UserRole{id=4}}}
Client{id=1, user=User{id=5, userRole=UserRole{id=1}}}
WORKAROUND
I tried to reach the goal by use of Spring JPA but could'nt.
The workaround that keeps the referential integrity was by creating a constrains through DB like below and add #PrePersist and #PreUpdate annotated method which is updating the client's roleId as intended.
create table clients
(
client_id integer not null,
client_user_id integer,
client_role_id integer,
primary key (client_id)
);
create table user_roles
(
role_id integer generated by default as identity,
primary key (role_id)
);
create table users
(
user_id integer generated by default as identity,
user_role_id integer,
primary key (user_id),
CONSTRAINT User_Role UNIQUE (user_id, user_role_id)
);
alter table users
add constraint FK_role_id foreign key (user_role_id) references user_roles (role_id);
alter table clients
add constraint FK_user_id foreign key (client_user_id, client_role_id) references users (user_id, user_role_id) on update cascade ;
Thanks to that I could for instance update userRole in user entity, and the change was reflected in the clients table as well without any further actions
I'm trying to have Spring Data JPA issue one query using joins to eagerly get a graph of entities:
#Entity
#NamedEntityGraph(name = "PositionKey.all",
attributeNodes = {#NamedAttributeNode("positionKey.account"),
#NamedAttributeNode("positionKey.product")
})
#Data
public class Position {
#EmbeddedId
private PositionKey positionKey;
}
#Embeddable
#Data
public class PositionKey implements Serializable {
#ManyToOne
#JoinColumn(name = "accountId")
private Account account;
#ManyToOne
#JoinColumn(name = "productId")
private Product product;
}
Here's my Spring Data repo:
public interface PositionRepository extends JpaRepository<Position, PositionKey> {
#EntityGraph(value = "PositionKey.all", type = EntityGraphType.LOAD)
List<Position> findByPositionKeyAccountIn(Set<Account> accounts);
}
This produces the following exception:
java.lang.IllegalArgumentException: Unable to locate Attribute with the the given name [positionKey.account] on this ManagedType
I want all of the accounts and products to be retrieved in one join statement with the positions. How can I do this / reference the embedded ID properties?
I would suggest refactoring the entity this way if it possible
#Entity
#NamedEntityGraph(name = "PositionKey.all",
attributeNodes = {#NamedAttributeNode("account"),
#NamedAttributeNode("product")
})
#Data
public class Position {
#EmbeddedId
private PositionKey positionKey;
#MapsId("accountId")
#ManyToOne
#JoinColumn(name = "accountId")
private Account account;
#MapsId("productId")
#ManyToOne
#JoinColumn(name = "productId")
private Product product;
}
#Embeddable
#Data
public class PositionKey implements Serializable {
#Column(name = "accountId")
private Long accountId;
#Column(name = "productId")
private Long productId;
}
Such an EmbeddedId is much easier to use. For instance, when you are trying to get an entity by id, you do not need to create a complex key containing two entities.
I'm writing 3 tables in the following relation:
Club class:
#Setter
#Getter
#Entity
#Table(name = "Club")
public class Club {
#Id
#GeneratedValue
private Long id;
private String name;
private String type;
private String mainPage;
private String logo;
#OneToMany(mappedBy="clubProductKey.club", cascade = CascadeType.ALL)
#JsonIgnoreProperties(value = "clubProductKey.club", allowSetters=true)
private Set<ClubProduct> clubProducts;
...
Product class:
#Setter
#Getter
#Entity
#Table(name = "Product")
public class Product {
#Id
#GeneratedValue
private Long id;
#OneToMany(mappedBy="clubProductKey.product", cascade = CascadeType.ALL)
#JsonIgnoreProperties(value = "clubProductKey.product", allowSetters=true)
private Set<ClubProduct> clubProducts;
...
ClubProduct class:
#Setter
#Getter
#Entity
#Table(name = "ClubProduct")
public class ClubProduct {
#EmbeddedId
private ClubProductKey clubProductKey;
...
ClubProductKey class:
#Setter
#Getter
#Embeddable
public class ClubProductKey implements Serializable {
#ManyToOne(cascade = {CascadeType.MERGE,CascadeType.REFRESH })
#JoinColumn(name = "club_id", referencedColumnName = "id")
#JsonIgnoreProperties(value = "clubProducts", allowSetters=true)
private Club club;
#ManyToOne(cascade = {CascadeType.MERGE,CascadeType.REFRESH })
#JoinColumn(name = "product_id", referencedColumnName = "id")
#JsonIgnoreProperties(value = "clubProducts", allowSetters=true)
private Product product;
...
ClubProductRepository class:
public interface ClubProductRepository extends JpaRepository<ClubProduct, ClubProductKey> {
public List<ClubProduct> findByClubProductKeyClub(Club club);
public List<ClubProduct> findByClubProductKeyProduct(Product product);
}
I try to save clubProduct like this:
#Service
public class ClubProductServiceImp implements ClubProductService {
#Autowired
private ClubProductRepository clubProductRepository;
...
ClubProduct savedClubProduct = clubProductRepository.save(clubProduct);
return savedClubProduct;
}
However I find that the clubProduct is not saved in the clubProducts list in the club or product entity, the list is null. Must I add lines like club.getClubProducts.add(clubProduct) or is there any other way to make it added automatically?
Thank you.
The #OnetoMany mapping in your Club class uses the attribute mappedby which means that it represents the owning side of the relation responsible for handling the mapping. However, we still need to have both sides in sync as otherwise, we break the Domain Model relationship consistency, and the entity state transitions are not guaranteed to work unless both sides are properly synchronized.
The answer is yes, you have to manage the java relations yourself so that the clubProducts gets persisted. You are using an instance of the repository class club to persist the data so , you should add a setter method like :
public void addClubProduct(ClubProduct clubProduct) {
if (clubProduct!= null) {
if (clubProduct== null) {
clubProduct= new ArrayList<ClubProduct>();
}
clubProducts.add(clubProduct);
clubProduct.setClubProduct(this);
}
}
also a method to remove it from the list and use these method in your code to set the values to the list properly before initiating save . Read related article
I have created two Entities namely Teacher and Detail, the code snippet is shown below
Teacher.java
#Entity
#Table(name = "teacher")
public class Teacher implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id")
private long id;
#Column(name = "name")
private String name;
#Column(name = "age")
private int age;
#OneToOne(mappedBy = "teacher", cascade = CascadeType.ALL)
private Detail detail;
public Teacher() {
}
public Teacher(String name, int age) {
this.name = name;
this.age = age;
}
//getter and setter
}
Detail.java
#Entity
#Table(name = "detail")
public class Detail implements Serializable {
#Id
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "id")
private Teacher teacher;
#Column(name = "subjects")
private String subjects;
public Detail() {
}
public Detail(String subjects) {
this.subjects = subjects;
}
//getter and setter
}
I am trying to achieve one to one mapping with the shared primary key concept
but when i execute the controller, only Teacher table is updating with the value
try {
Teacher teacher=new Teacher("xyz",23);
Detail detail=new Detail("Java,c,c++");
teacher.setDetail(detail);
session.beginTransaction();
session.save(teacher);
session.getTransaction().commit();
model.addAttribute("added", "data inserted");
session.close();
}
After executing only Teacher table is updated with the specified values.Detail table is still showing empty
It does not work exactly like that. You still need the id field in your Detail, so add:
#Id
private long id;
to your Deatail class.
And - as comment suggests - replace the #Id annotation in field Teacher to #MapsId. This way the id of Teacher is mapped to the id of Detail BUT ONLY if you also set the teacher to the detail - you always need to set both sides of relationship - like:
teacher.setDetail(detail);
detail.setTeacher(teacher);
I need a many to many hibernate mapping needed 3 joins. I've tried to find out a solution without intermediate entity like LecturerCourse.
I have a many to many relation in my database between my lecturer and course tables. A course can be given by several lecturer while a lecturer can give several courses.
I have courses stored before hand. However, I need to assign courses to lecturer. When I assign courses I also store the capacity of that course.
My database diagram:
I use hibernate and spring. I need a hibernate mapping when a course is assign any lecturer. I need to add values to capacity field.
My lecturer mapping :
#Entity
#Table(name="LECTURER")
public class Lecturer {
#Id
#GeneratedValue(strategy=GenerationType.SEQUENCE, generator="LECTURER_ID_SEQ")
#SequenceGenerator(name="LECTURER_ID_SEQ", sequenceName="LECTURER_ID_SEQ")
private Long Id;
#Column(name="NAME")
private String name;
#Column(name="SURNAME")
private String surname;
#Column(name="EMAIL")
private String email;
#Column(name="USERNAME")
private String username;
#Column(name="PASSWORD")
private String Password;
#ManyToMany
#JoinTable(
name="LECTURER_COURSE",
joinColumns=#JoinColumn(name="LECTURER_ID"),
inverseJoinColumns=#JoinColumn(name="COURSE_ID")
)
private List<Course> courses;
//getters - setters
}
My course mapping :
#Entity
#Table(name="COURSE")
public class Course {
#Id
#GeneratedValue(strategy=GenerationType.SEQUENCE, generator="COURSE_ID_SEQ")
#SequenceGenerator(name="COURSE_ID_SEQ", sequenceName="COURSE_ID_SEQ")
private Long id;
#Column(name="NAME")
private String name;
#Column(name="CODE")
private String code;
}
Any idea how to solve my problem ?
You need to use #EmbeddedId and #Embeddable annotations to solve this issue:
Lecturer Class:
#Entity
#Table(name="LECTURER")
public class Lecturer {
#OneToMany(fetch = FetchType.LAZY, mappedBy = "pk.lecturer", cascade=CascadeType.ALL)
Set<LecturerCourse> lecturerCourses == new HashSet<LecturerCourse>();
//all others properties Setters and getters are less relevant.
}
Course class:
#Entity
#Table(name="COURSE")
public class Course {
#OneToMany(fetch = FetchType.LAZY, mappedBy = "pk.course", cascade=CascadeType.ALL)
Set<LecturerCourse> lecturerCourses == new HashSet<LecturerCourse>();
//all others properties Setters and getters are less relevant.
}
LecturerCourse Class:
#Entity
#Table(name = "lecturer_course")
#AssociationOverrides({
#AssociationOverride(name = "pk.lecturer",
joinColumns = #JoinColumn(name = "LECTURER_ID")),
#AssociationOverride(name = "pk.course",
joinColumns = #JoinColumn(name = "COURSE_ID")) })
public class LecturerCourse {
private LecturerCourseID pk = new LecturerCourseID();
#Column(name = "CAPACITY", nullable = false, length = 10)
private String capacity;
#EmbeddedId
public LecturerCourseID getPk() {
return pk;
}
}
Now the Primary Key:
#Embeddable
public class LecturerCourseID implements java.io.Serializable {
private Lecturer lecturer;
private Course course;
#ManyToOne
public Stock getLecturer() {
return lecturer;
}
public void setLecturer(Lecturer lecturer) {
this.lecturer= lecturer;
}
#ManyToOne
public Course getCourse() {
return course;
}
public void setCourse(Course course) {
this.course= course;
}
}
now Your Main should be something like this:
Lecturer lecturer1 = new Lecturer();
Course math = new Course();
LecturerCourse lecturer1math = new LecturerCourse();
lecturer1math.setCapacity("capacity");
lecturer1math.setLecturer(lecturer1);
lecturer1math.setCourse(math);
lecturer1.getLecturerCourses().add(lecturer1math);
//saving object
session.save(lecturer1);
You need to be sure that class marked as #Embeddable should implement Serializable marker interface.
Hope it helps.