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;
Related
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 and having a use case where there are 2 kinds of users namely the "clients" and "professionals". These 2 entities have a parent entity called the "users" where each "user" has one entry in either "client/professional" depending on their role.
Let's consider a "clients".
A "user" has a one-to-one mapping with a "client"
A client might have several "companies" under him, i.e "client" has one-to-many relationship with "companies".
I am creating a REST API for this use case using spring boot. I still dont have any idea about why i should be using mapping in Hibernate. So far the only advantage i see is that, the CASCADING property of it. If a "user" gets removed, all the tables having the "user-id" will also be flushed. But consider a scenario where i need to add "companies" for a "client". I am confused to whether i should persist "companies" via "clients" entity or should i directly persist to "client" entity. I dont see any major advantage here because in both cases we are checking whether a "client" exists with the given ID before persisting in the "clients" table.
User Entity
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long UID;
private Integer userRoleId;
private String username;
private String email;
private String phoneNumber;
private String firstName;
private String lastName;
private Long dateOfJoin;
private Boolean activeStatus;
private Long createdAt;
private Long updatedAt;
#OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "user")
private Client client;
}
Client Entity
public class Client {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long CID;
#Column(unique = true)
private Long userId;
private Long createdAt;
private Long updatedAt;
#OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "client")
private ClientCompany clientCompany;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "userId" ,referencedColumnName = "UID", insertable = false, updatable = false)
private User user;
}
Client Company Entity
public class ClientCompany {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long CCID;
private Long clientId;
private String email;
private String phoneNumber;
public String streetAddress1;
public String streetAddress2;
public String zipCode;
public String city;
public String state;
public String country;
private Long createdAt;
private Long updatedAt;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "clientId", referencedColumnName = "CID", insertable = false, updatable = false)
private Client client;
}
The advantage of using Hibernate/JPA is that you do not need to code JDBC calls.
You just use objects.
In your scenario,
load a Client instance from the database;
create a ClientCompany object;
assign the Client instance to it (no need to check the client existence since you loaded it from the database);
save to database.
Hibernate will take care of everything without you writing any SQL statements.
Step 1) can also be replaced with creating a new Client that will be saved to the database, but again Hibernate will handle saving correctly (if you configured it correctly).
I have 2 tables namely user & user_session.
User table has user_id as a primary key which is referrers to user_session table.
Plus user_session has composite key including session_intime and user_id.
I have designed my entity in JPA. Now I want to map these two entities. I have tried to map these two tables. But my application build failed. Can you please help me out?
#Entity
#Table(name="user")
public class User {
#Id
#Email
#Column(name = "user_id")
private String userId;
#Column(name = "password")
private String password;
#Column(name = "fname")
private String fname;
#OneToMany(fetch = FetchType.LAZY)
#JoinColumn(name = "userId", referencedColumnName = "user_id")
private UserSession userSession;
}
#Entity
#Table(name="user_session")
public class UserSession{
#EmbeddedId
private UserSessionPK userSessionPK;
#Column(name = "remote_ip")
private String remoteIp;
}
#Embeddable
public class UserSessionPK implements Serializable {
private static final long serialVersionUID = 1L;
#Column(name = "user_id")
private String userId;
#Temporal(TemporalType.TIMESTAMP)
#Column(name = "time_in")
private Date timeIn;
}
I want to map user_id of User table to user_id of UserSessionPK. I am new to JPA, so I don't know how to map with embeddable class.
Remove the mappedBy attribute. This attribute is used when you have bidirectional relationship to indicate which side of the relationship is the owner.
But you will need to set the Foreign Key aka JoinColumn
#JoinColumn("user_id")
#OneToMany(fetch = FetchType.LAZY)
private UserSession userSession;
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.
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.