I am new to Spring/JPA and I am trying to use Database relationship #annotations to simplify my code.
I have two entities, a User and Token entity.
When setToken() is called on the User, I want the Token to overwrite any old tokens associated with the user in the table.
At the moment, the new token (via user.setToken()) is being INSERT rather than UPDATE.
How do I go about achieving this relationship? In "Lame-mans"...A user can only even have one token and can be given another at any time, discarding the old.
There are extra fields in these models that i have truncated for clarity.
#Entity
#Table(name = "Users")
public class User {
#Column(name = "USER_ID")
#Id #GeneratedValue(strategy = GenerationType.IDENTITY)
#JsonInclude(JsonInclude.Include.NON_NULL)
private Long userId;
#OneToOne(fetch = FetchType.LAZY,cascade = CascadeType.ALL)
#JoinColumn(name = "REFRESH_TOKEN_ID")
private RefreshToken refreshToken;
...setters and getters
And the code for a token:
#Entity
#Table(name = "RefreshTokens")
public class RefreshToken {
#Column(name = "REFRESH_TOKEN_ID")
#Id #GeneratedValue(strategy = GenerationType.IDENTITY)
private Long tokenId;
If your RefreshToken has only 1 Field REFRESH_TOKEN_ID which is long. Why you need different table for this. You can just have something like this
public class User {
#Column(name = "USER_ID")
#Id #GeneratedValue(strategy = GenerationType.IDENTITY)
#JsonInclude(JsonInclude.Include.NON_NULL)
private Long userId;
#Column(name = "REFRESH_TOKEN_ID")
private Long refreshToken;
...
When setToken() is called you must be setting any value. If yes thats it. Your logic will work fine,
If no you can always generate a Unique value in Java based on Current time or something else.
or
If you want to continue with same patter use orphanRemoval = true
#OneToOne(fetch = FetchType.LAZY,cascade = CascadeType.ALL, orphanRemoval = true)
#JoinColumn(name = "REFRESH_TOKEN_ID")
private RefreshToken refreshToken;
You should never modify the primary key of a an entity
This is not be possible as you change the id of the token. You need to create a different id in the RefreshToken thats unique and stays the same after save.
If you really do need that - you'd better of delete the entity and create a new one which just copies the old one but with a new primary key.
Related
I have one to many relation ship between a User and UserRole.
public class User {
#Id
#GeneratedValue
private long id;
#Column(unique = true)
private String username;
private String password;
#OneToMany(fetch=FetchType.EAGER)
#JoinTable(
name = "user_roles",
joinColumns = {#JoinColumn(name="userId")},
inverseJoinColumns = {#JoinColumn(name="roleId")}
)
private Collection<UserRole> roles;
}
and
public class UserRole {
#Id
#GeneratedValue
private long id;
#Column(unique = true)
private String roleName;
}
I am able to save a user at first. But when I try to save another user it rejects with an exception of duplicated entry on the junction table
One thing I noticed is when we have One-to-Many association the many side foreign key will be a primary key on the junction table. So, I need to make the relation Many-to-Many. So that the combination of both foreign keys will serve as a composite key.
Let's se we have Hibernate entity User with basic fields such as username, password, roles etc..
Now we have an entity such as Car.
User has a OneToOne relationship with Car, cause he can own a car. But he also has besides this a OneToMany relationship to Car, because he also owns the cars of his children. But in the frontend I want to know which cars he owns for himself and which cars he owns for his children. The same applies to the relationship between User and motorbike (his own, his childrens, etc...)
How would the User entity class look like? Is it good to have the relationships mapped in an "Helper" entity such as UserData:
#Entity
#Data
#Table( name = "users",
uniqueConstraints = {
#UniqueConstraint(columnNames = "username")
})
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#NotBlank
#Size(max = 150)
private String username;
#NotBlank
#Size(max = 120)
private String password;
#OneToOne(cascade = {CascadeType.ALL}, fetch = FetchType.EAGER)
#JoinColumn(name = "USER_DATA_ID")
private UserData userData;
UserData:
#Entity
#Data
#Table( name = "user_data")
public class UserData {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToOne(cascade = {CascadeType.ALL}, fetch = FetchType.EAGER)
#JoinColumn(name = "OWN_CAR_ID")
private Car ownCar;
#OneToOne(cascade = {CascadeType.ALL}, fetch = FetchType.EAGER)
#JoinColumn(name = "PARTNER_CAR_ID")
private Car partnerCar;
#ManyToMany(fetch = FetchType.LAZY)
#JoinTable( name = "user_children_cars",
joinColumns = #JoinColumn(name = "user_data_id"),
inverseJoinColumns = #JoinColumn(name = "car_id"))
private Set<Car> childrenCars = new HashSet<>();
public boolean addToChildrenCarSet(Car c) {
return childrenCars.add(c);
}
public UserData() {
}
}
As you ask for an opinion, I would say it gets unnecessary complicated if you use the intermediate entity user_data. :-) There is no real drawback to add more fields and keys into the user class - performance is probably also better then using the EAGER fetching. If performance is an issue, better optimize querys later on then splitting the table now.
Also the #ManyToMany I would avoid - better create the intermediate table and relations yourself. You can check out https://bootify.io and create your database schema there. There is no EAGER fetching and also no CascadeType.ALL (both only good ideas in special cases), you would probably add more problems with that then actual helping in any way.
So the addToChildrenCarSet method would end up in a #Service class, in a method with #Transactional, in my proposal.
I'm trying to connect an entity (User) to entities they create which will be Surveys.
I have two repositories, one UserRepository and one SurveyRepository. I can load Surveys according to which User has them and currently they are all mapped by the User_ID, which is a field on the Survey entity.
However, when I try to remove a Survey, this removes my User whenever I define CascadeType.ALL.
But when I don't use that, I get another error "Caused by: java.sql.SQLIntegrityConstraintViolationException:"
I'm gussing this is all related to the password encryption I'm using, but I am not even trying to delete the User entity, I'm just deleting the Survey, which holds a reference, or an ID to the Survey..
I've tried CascadeType.All on both sides, and I've tried not having any CascadeType at all as well.. If I have it on both sides, this deletes the user whenever I tell my surveyRepository.delete(currentSurvey);
And whenever I don't have it on both sides, I get the exception above..
User Entity:
#Entity
#Table(name = "user")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "user_id")
private Long id;
#NotEmpty
#Email
#Column(unique = true)
private String email;
private String password;
#NotBlank
private String username;
#NotBlank
private String firstName;
#NotBlank
private String lastName;
#NotBlank private String role;
#OneToMany(fetch = FetchType.EAGER)
private Set<Survey> surveys = new HashSet<>();
Survey Entity:
#Entity
#Table(name = "survey")
public class Survey {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "survey_id")
private Long id;
private String title, creator, description;
private LocalDate date = LocalDate.now();
#OneToMany(orphanRemoval = true, cascade = CascadeType.ALL, fetch = FetchType.EAGER)
#JoinColumn(name = "survey_id")
#OrderBy("position ASC")
private Set<Question> questions = new HashSet<>();
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "user_id")
private User user;
I'm just not sure how I can tell JPA/Hibernate not to touch the User whenever we delete the Survey.
It doesn't matter if I save the User with Survvey or not does it?
Basically I've tried a lot of options and I figure I'm not quite grasping the issue, and I suspect it's about the annotations on the User side, but I still feel as if I should be able to delete the child entity with no problem at all since I am not touching the parent entity?
This is because of EAGER fetch type in User class for surveys.
You delete survey but because it is existed on surveys set in user yet, it wouldn't be deleted actually.
You need to do like this:
// User class
#OneToMany(cascade=CascadeType.ALL, orphanRemoval=true, mappedBy="user")
private Set<Survey> surveys = new HashSet<>();
//Survey class
#ManyToOne
#JoinColumn(name = "user_id")
private User user;
I have SpringBoot 2.1.3 and Java 8 application. Building DB with JPA I have 3 table in one to one relationship. Suppose the tables is the follows:
#Entity
#Data //lombok
#Table(name = "users")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "id")
private Long id;
#OneToOne(mappedBy = "user", cascade = CascadeType.ALL)
private Address address;
}
And then:
#Entity
#Data
#Table(name = "address")
public class Address {
#Id
#Column(name = "id")
private Long id;
#OneToOne
#MapsId
private User user;
}
That's works.. and it is the best way to do (this exactly example is taken from documentation).
If I start the application the DB is created and if I tried to add entities all works well. The model created follows:
Now I want to add a Country object to my address Entities (for example) and I modified the Entities as follows:
#Entity
#Data
#Table(name = "address")
public class Address {
#Id
#Column(name = "id")
private Long id;
#OneToOne
#MapsId
private User user;
#OneToOne
#MapsId
private Country country;
}
And Country Entities:
#Entity
#Data
#Table(name = "country")
public class Country {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "id")
private Long id;
#OneToOne(mappedBy = "country", cascade = CascadeType.ALL)
private Address address;
}
The application still starts, the DB is created and the model follows:
But if I try to save a User as follows:
User user = new User();
Address address = new Address();
Country country = new Country();
user.setAddress(address);
address.setUser(user);
address.setCountry(country);
country.setAddress(address);
userRepository.save(user);
I obtain the error:
java.sql.SQLException: Field 'country_id' doesn't have a default value
Anyway I solve the issue removing #MapsId and added #JoinColumn but I would like to understand what's wrong.
P.S.: I'm using MySQL 5.7 with InnoDB dialect (setting on application.properties)
Thanks all
It works only with one #MapsId annotation. Using two is causing that country id is not inserted:
insert into Country (id) values (?)
insert into Users (id) values (?)
insert into Address (user_id) values (?)
I have many to many relation between User and Event. I need to have extra column in relational table. I did id:
#Entity
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
#OneToMany(mappedBy="user")
private Set<EventUser> eventUsers = new HashSet<>();
//
}
#Entity
public class Event {
#Id
#GeneratedValue(strategy= GenerationType.AUTO)
private long id;
#OneToMany(mappedBy="event")
private Set<EventUser> eventUsers = new HashSet<>();
//
}
#Entity
#Table(name = "Event_User")
public class EventUser {
#Id
#GeneratedValue(strategy= GenerationType.AUTO)
private long id;
private String reaction;
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "user_id")
private User user;
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "event_id")
private Event event;
//
}
But now... I don't know how to load all events where user has concrete email. Before it I used method:
findByUsersEmail(String email);
Now I can't do this, because Event doesn't have Set users field.
Any ideas ?
What you need here is property-expressions.
Just a quick idea to start:
findByEventUsers_UserEmail(String email);
Note: Dont forget that creating queries by method names is a very limited approach and only used by trivial cases. In any other case, don't be afraid of using the #Query annotation on the method or write JPQL/Criteria API manually.