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How to access data in bidirectional many to many mapping

UserDetail.java (model class)
#Entity
public class UserDetail {
#Id
private String email;
private String name;
private String password;
#ManyToMany(cascade = CascadeType.ALL)
private List<Role> role;
#ManyToMany(cascade = CascadeType.ALL,mappedBy = "user")
private List<GroupDetail> group;
}
GroupDetail.java ( model class)
#Entity
public class GroupDetail {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private int id;
#Column(unique = true)
private String groupName;
#ManyToMany(cascade = CascadeType.ALL)
private List<UserDetail> user;
#ManyToMany(cascade = CascadeType.ALL)
private List<Role> role;
}
Here as you can see GroupDetail is the owner of the association and Hibernate will only check that side when maintaining the association.
So, how do i get List of GroupDetail using the user email?

Following should work for you:
select userDtl.group from UserDetail userDtl where userDtl.email = 'Your Email'
If this does not work, then you could try to use join explicitly like this:
select g from UserDetail u join u.group g where u.email = 'Your Email'

Do this, add getter and setter in both entities.
UserDetails user = em.find(UserDetails.class, emailId);
List<GroupDetail> group = user.getGroup();

Hibernate user_roles table will not update when using ManyToOne relationship

I have 3 tables, User, Role, and User_role. User has a OneToMany relationship mapped by "user" with a CascadeType.Merge and user_role has 2 ManyToOne Relationships with cascadeTypes.All however the user_table never populates with data when running hibernate. Instead values are only populated in the user and role tables, but never the user_role table.
User Table Definition
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name="Id", nullable=false, updatable = false)
private Long id;
private String username;
private String password;
private String firstName;
private String lastName;
private String email;
private String phone;
private boolean enabled = true;
#OneToMany(mappedBy = "user", cascade=CascadeType.MERGE, fetch =
FetchType.EAGER)
#JsonIgnore
private Set<UserRole> userRoles = new HashSet<>();
UserRole Table:
#Entity
#Table(name="user_role")
public class UserRole implements Serializable {
private static final long serialVersionUID = 890345L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long userRoleId;
#ManyToOne(fetch = FetchType.EAGER, cascade=CascadeType.ALL,
optional=false)
#JoinColumn(name = "user_id")
private User user;
#ManyToOne(fetch = FetchType.EAGER, cascade=CascadeType.ALL,
optional=false)
#JoinColumn(name = "role_id")
private Role role;
public UserRole () {}
public UserRole (User user, Role role) {
this.user = user;
this.role = role;
}
public long getUserRoleId() {
return userRoleId;
}
public void setUserRoleId(long userRoleId) {
this.userRoleId = userRoleId;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public Role getRole() {
return role;
}
public void setRole(Role role) {
this.role = role;
}
}
Call To userRepository.save() in userServiceImpl that is called from a commandLine Runner.
#Service
public class UserServiceImpl implements UserService {
private static final Logger LOG = LoggerFactory.getLogger(UserSecurityService.class);
#Autowired
private UserRepository userRepository;
#Autowired
private RoleRepository roleRepository;
// Indicates a Database Transaction
#Transactional
public User createUser(User user, Set<UserRole> userRoles) {
User localUser = userRepository.findByUsername(user.getUsername());
if(localUser != null) {
LOG.info("User with username {} already exist. Nothing will be done. ", user.getUsername());
} else {
for (UserRole ur : userRoles) {
roleRepository.save(ur.getRole());
}
Set<UserRole> currentRoles =user.getUserRoles();
currentRoles.addAll(userRoles);
user.setUserRoles(currentRoles);
localUser = userRepository.save(user);
}
return localUser;
}
}
Main Class Run()
public void run(String... args) throws Exception {
User user1 = new User();
user1.setFirstName("John");
user1.setLastName("Adams");
user1.setUsername("j");
user1.setPassword(SecurityUtility.passwordEncoder().encode("p"));
user1.setEmail("JAdams#gmail.com");
Set<UserRole> userRoles = new HashSet<>();
Role role1 = new Role();
role1.setRoleId(1);
role1.setName("ROLE_USER");
userRoles.add(new UserRole(user1, role1));
userService.createUser(user1, userRoles);
}

CascadeType.MERGE will only cascade merge events. Persist events wont cascade so if you try to save a new user, the persist event will not cascade to User_role and no entries will be inserted into the user_role table.
Try to add the CascadeType.PERSIST or change to CascadeType.ALL in order to cascade save the record in the database.
#OneToMany(mappedBy = "user", cascade={CascadeType.MERGE, CascadeType.PERSIST}, fetch = FetchType.EAGER)
You can find out more about Cascade events in this answer: What do REFRESH and MERGE mean in terms of databases?

I was able to persist the data to the user_role associative table by implementing the JPA entity manager. A new EntityManager class was instantiated and the data was persisted through the javax.persistence .merge() method.

updating an entity in many-to-many relationship

I have a Spring project that uses JPA with Hibernate and MySQL database. Database includes three tables: Users, Roles, and many-to-many join table UserRoles.
Below are the corresponding classes for the tables.
ApplicationUser.java
#Entity
#Table(name = "APPLICATION_USER")
public class ApplicationUser extends ExtAuditInfo {
public static final Long SYSTEM_USERID = 1000L;
#Id
#Column(name = "APPLICATION_USER_ID")
private long applicationUserId;
#Column(name = "LOGIN_NAME")
private String loginName;
#Column(name = "LAST_NAME")
private String lastName;
#Column(name = "FIRST_NAME")
private String firstName;
#Column(name = "MIDDLE_NAME")
private String middleName;
#OneToMany(mappedBy = "id.applicationUser", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private List<UserRole> roles =new ArrayList<>();
//get and set methods
Role.java
#Entity
#Table(name = "ROLE")
#NamedQueries({
#NamedQuery(name = "Role.getRoleById", query = "select r from Role r where r.roleId =:roleId"))}
public class Role extends AuditInfo {
#Id
#Column(name="ROLE_ID")
private long roleId;
#Column(name="ACTIVE_FLAG")
private String activeFlag;
#Column(name="ROLE_NAME")
private String roleName;
#OneToMany(mappedBy = "id.role", fetch = FetchType.LAZY)
private List<UserRole> users = new ArrayList<>();
//get and set methods
UserRole.java
#Entity
#AssociationOverrides({
#AssociationOverride(name = "id.applicationUser",
joinColumns = #JoinColumn(name = "APPLICATION_USER_ID")),
#AssociationOverride(name = "id.role",
joinColumns = #JoinColumn(name = "ROLE_ID")) })
#Table(name = "USER_ROLE")
public class UserRole extends ExtAuditInfo implements Serializable{
#EmbeddedId
private UserRoleID id = new UserRoleID();
#Column(name="USER_ROLE_VER")
private long userRoleVer;
public UserRole(){
}
#Transient
public ApplicationUser getApplicationUser() {
return this.id.getApplicationUser();
}
public void setApplicationUser(ApplicationUser applicationUser) {
this.id.setApplicationUser(applicationUser);
}
public long getUserRoleVer() {
return this.userRoleVer;
}
public void setUserRoleVer(long userRoleVer) {
this.userRoleVer = userRoleVer;
}
#Transient
public Role getRole() { return this.id.getRole(); }
public void setRole(Role role) { this.id.setRole(role); }
}
UserRoleID.java
#Embeddable
public class UserRoleID implements Serializable {
#ManyToOne(cascade = CascadeType.ALL)
private ApplicationUser applicationUser;
#ManyToOne(cascade = CascadeType.ALL)
private Role role;
private static final long serialVersionUID = 1L;
public UserRoleID() {
}
public ApplicationUser getApplicationUser() {
return this.applicationUser;
}
public void setApplicationUser(ApplicationUser applicationUser) {
this.applicationUser = applicationUser;
}
public Role getRole() {
return this.role;
}
public void setRole(Role role) {
this.role = role;
}
}
Now, when I create a sample user with viewer role, the record is being inserted into the Application_user and User_Role tables, but when I try to update the role of the user it is adding a new role to the user instead of updating the existing role.
This is what I'm doing
#TransactionAttribute(TransactionAttributeType.REQUIRED)
public void updateRole(ApplicationUser appUser, long roleId){
EntityManager em=getEntityManager();
TypedQuery<Role> query = em.createNamedQuery("Role.getRoleById", Role.class);
query.setParameter("roleId",roleId);
Role r = query.getSingleResult();
UserRole userRole= appUser.getRole().get(0);
userRole.setRole(r);
em.merge(userRole);
em.flush();
em.detach(userRole);
}
Any idea, what to do to update the existing role instead of creating a new role in user_role table?

You are assigning new role to user, so a new record is added in user_role table, and old user_role entry is deleted. That's the right behavior.
So it's not you called "update the role of user".
Update:
You should delete role manually when many-to-many relationship.
appUser.getRoles().remove(userRole);
em.remove(userRole);
UserRole newUserRole = new UserRole();
newUserRole.setRole(r);
appUser.getRoles().add(newUserRole);

many-to-many-relationship between two entities in spring boot

I have two Entities in my Spring-Boot Application:
User.java
#Entity
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
Long id;
String firstname;
String lastname;
String username;
String password;
}
and
Role.java
Entity
#Table(name = "role")
public class Role {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
Long id;
String name;
String description;
}
for my MySql database
I have excluded the getter and setter methods for this question.
I want to realise a Many-to-Many-Relationship between both Entities. Every user should be able to assign multiple roles to himself
I already Created a mapping table for both tables in my database. It has the rows
user_id
role_id.
I also created a new Entity UserRole.java which looks like this:
#Entity
#Table(name = "user_role")
public class UserRole implements Serializable{
private User user;
private Role role;
#Id
#ManyToOne
#JoinColumn(name = "user_id")
public User getuser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
#Id
#ManyToOne
#JoinColumn(name = "role_id")
public Role getrole(){
return role;
}
public void setRole(Role role){
this.role = role;
}
}
Now my question: is this construction correct? If yes, how do i add existing roles to an existing user and get the roles of this user in spring-boot?

You can find any tutorial connected with many-to-many relationship using Hibernate/Spring Data, example:
Spring Data many-to-many
With your model it's simple to add the relationship mappings, like this:
#Entity
public class Role {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
private String description;
#ManyToMany(cascade = CascadeType.ALL)
#JoinTable
private Set<User> users;
}
and this:
#Entity
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String firstname;
private String lastname;
private String username;
private String password;
#ManyToMany(mappedBy = "users")
private Set<Role> roles;
}

JPA join in spring boot application

I've read examples but have my personal question to you.
I have 2 tables:
Role:
id, name
User:
id, login, name, role_id
Role entity
#Entity
#Table(name = "role")
public class Role {
#Id
#Column(name = "id")
private long id;
#Column(name = "name", length = 45)
private String name;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "role")
private Set<User> user = new HashSet<>();
//getters and setters
User entity
#Entity
#Table(name = "user")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "id",insertable = false, updatable = false)
private long id;
#Column(name = "login")
private String login;
#Column(name = "user_name")
private String userName;
#ManyToOne(fetch = FetchType.LAZY)
private Role role;
//getters and setters
And repository:
public interface UserRepository extends JpaRepository<User, Long> {
String Q_GET_ALL_USERS = "from User u left join Role r on u.role_id=r.id";
#Query(Q_GET_ALL_USERS)
Collection<User> getAllUsers();
This code is showing: Caused by: java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: Path expected for join! [from com.example.jpa.model.User u left join Role r on u.role_id=r.id]
How I understand entity can't contains 'id' (in my case in Role) for references and I should remove this field. But entity should have '#Id'.
In this case I should create new column in 'Role'? or I can use more beautiful decision?
I put all project to bb

To use join in HQL (JPQL) you don't need on clause
String Q_GET_ALL_USERS = "select u from User u left join u.role";
This query doesn't have any sence because of you don't use role in the where clause.
If you want to get users with a fetched role you can use join fetch
String Q_GET_ALL_USERS = "select u from User u left join fetch u.role";
Update
Your schema for User and Role is not commonly used. I advice to you make #ManyToMany association from user to roles and remove any user association from the Role
#Entity
#Table(name = "user")
public class User {
#ManyToMany(fetch = FetchType.LAZY)
private Set<Role> roles;
}
#Entity
#Table(name = "role")
public class Role {
#Id
#Column(name = "id")
private long id;
#Column(name = "name", length = 45)
private String name;
}

No, you should create a new column in User.
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "role_id")
private Role role;

Thank you all for answers. Right entities and query below (plus tables schema).
Tables (queries)
CREATE TABLE role (
id INT NOT NULL PRIMARY KEY,
name VARCHAR(45) NOT NULL
);
CREATE TABLE user (
id INT NOT NULL PRIMARY KEY IDENTITY,
login VARCHAR(45) NOT NULL,
user_name VARCHAR(45) NOT NULL,
role_id INT NOT NULL,
FOREIGN KEY (role_id) REFERENCES role (id)
);
Entities:
#Entity
#Table(name = "user")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "id",insertable = false, updatable = false)
private long id;
#Column(name = "login")
private String login;
#Column(name = "user_name")
private String userName;
#ManyToOne(fetch = FetchType.LAZY)
private Role role;
//getters and setters
}
and
#Entity
#Table(name = "role")
public class Role {
#Id
#Column(name = "id")
private long id;
#Column(name = "name", length = 45)
private String name;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "role")
private Set<User> user = new HashSet<>();
//getters and setters
}
Repository
public interface UserRepository extends JpaRepository<User, Long> {
String Q_GET_ALL_USERS = "select u from User u left join u.role";
#Query(Q_GET_ALL_USERS)
Collection<User> getAllUsers();
}
#v-ladynev proposed alternative decision(use only #ManyToMany in User). More details you can find in comments under this answer.
When I check this decision I will update this answer (I hope I don't forget it :-))

Models
#Entity
#Table(name = "sys_std_user")
public class StdUser {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "class_id")
public int classId;
#Column(name = "user_name")
public String userName;
}
#Entity
#Table(name = "sys_std_profile")
public class StdProfile {
#Id
#Column(name = "pro_id")
public int proId;
#Column(name = "full_name")
public String fullName;
}
Controllers
#PersistenceUnit
private EntityManagerFactory emf;
#GetMapping("/join")
public List actionJoinTable() {
EntityManager em = emf.createEntityManager();
List arr_cust = em
.createQuery("SELECT u.classId, u.userName, p.fullName FROM StdUser u, StdProfile p WHERE u.classId=p.proId")
.getResultList();
return arr_cust;
}
Result:
[
[
1,
"Ram",
"Ram Pukar Chaudhary"
],
[
2,
"Raja",
"Raja Kishor Shah"
]
]