I have 3 entities in my spring boot App data rest, Appusers, Teacher, and Student
Appusers
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name= "appuserId", updatable=false)
private Long appuserId;
#Column(name = "username")
private String username;
#Column(name = "fullname")
private String fullName;
#Column(name = "email")
private String email;
#Column(name = "password")
private String password;
#OneToOne(mappedBy = "appuser")
private Teacher teacher;
#OneToOne(mappedBy = "appuser")
private Student student;
Teacher
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
#Column(name = "teacherId" , updatable = false)
private Long teacherId;
#Column(name= "firstname")
private String firstName;
#Column(name = "lastname")
private String lastName;
#Column(name="designation")
private String designation;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "appuserId", nullable = true)
private Appuser appuser;
#OneToMany(cascade = CascadeType.ALL, orphanRemoval=true ,mappedBy="teacher")
#JsonIgnore
private List<Course> courses;
Student
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name= "studentId", updatable=false)
private Long studentId;
#Column(name = "firstName")
private String firstName;
#Column(name = "lastName")
private String lastName;
#Column(name = "enrolledSince")
private String enrolledSince;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "appuserId", nullable = false)
private Appuser appuser;
#OneToMany(cascade = CascadeType.ALL,orphanRemoval=true, mappedBy="student")
#JsonIgnore
private List<CourseStudent> courseStudents;
i can insert in appusers table using json format in postman and it goes well. but when i try to insert in teacher or student table the result in appusers is null. it shouldnt be null because teacher and student foreign key to appusers.
This should not happen. When you save a teacher or a student you should specify appuser which is already in the database. And use appuserId instead Appuser, which is quite enough to identify to which appuser it belongs.
You can get your appuser after you save a teacher or a student and do request with join to the database.
when you try to insert in teacher or student table, please make sure that you are setting the value to appuser while persisting.
Student std =new Student();
// create an object of appuser,set its vaue and assign it to student object
Appuser ap = new Appuser();
// assigning values to the appuser object as ap.setfullname="...";... so on
std.setAppuser=ap;
now persist this student object the entries will be reflected in the mapped table
or you can set the id of appuser in std object that is already persisted .
Related
I am working on a Spring Boot project using Spring Data JPA and Hibernate mapping. I have the following doubt about how can I implement the following query.
I have an User entity class like this:
#Entity
#Table(name = "portal_user")
#Getter
#Setter
public class User implements Serializable {
private static final long serialVersionUID = 5062673109048808267L;
#Id
#Column(name = "id")
#GeneratedValue(strategy=GenerationType.IDENTITY)
private Integer id;
#Column(name = "first_name")
#NotNull(message = "{NotNull.User.firstName.Validation}")
private String firstName;
#Column(name = "middle_name")
private String middleName;
#Column(name = "surname")
#NotNull(message = "{NotNull.User.surname.Validation}")
private String surname;
#Column(name = "sex")
#NotNull(message = "{NotNull.User.sex.Validation}")
private char sex;
#Column(name = "birthdate")
#NotNull(message = "{NotNull.User.birthdate.Validation}")
private Date birthdate;
#Column(name = "tax_code")
#NotNull(message = "{NotNull.User.taxCode.Validation}")
private String taxCode;
#Column(name = "e_mail")
#NotNull(message = "{NotNull.User.email.Validation}")
private String email;
#Column(name = "pswd")
#NotNull(message = "{NotNull.User.pswd.Validation}")
private String pswd;
#Column(name = "contact_number")
#NotNull(message = "{NotNull.User.contactNumber.Validation}")
private String contactNumber;
#Temporal(TemporalType.DATE)
#Column(name = "created_at")
private Date createdAt;
#Column(name = "is_active")
private boolean is_active;
#OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, mappedBy = "user", orphanRemoval = true)
#JsonManagedReference
private Set<Address> addressesList = new HashSet<>();
#ManyToMany(cascade = { CascadeType.MERGE })
#JoinTable(
name = "portal_user_user_type",
joinColumns = { #JoinColumn(name = "portal_user_id_fk") },
inverseJoinColumns = { #JoinColumn(name = "user_type_id_fk") }
)
Set<UserType> userTypes;
#ManyToOne(fetch = FetchType.EAGER)
#JsonProperty("subagent")
private User parent;
public User() {
super();
}
public User(String firstName, String middleName, String surname, char sex, Date birthdate, String taxCode,
String email, String pswd, String contactNumber, Date createdAt, boolean is_active) {
super();
this.firstName = firstName;
this.middleName = middleName;
this.surname = surname;
this.sex = sex;
this.birthdate = birthdate;
this.taxCode = taxCode;
this.email = email;
this.pswd = pswd;
this.contactNumber = contactNumber;
this.createdAt = createdAt;
this.is_active = is_active;
}
}
The instances of this class represents users of my system. An user can have a single specific parent (the concept is similar to that of a referral: an user can bring another user in the system). This is handled by this ManyToOne recursive relationship:
#ManyToOne(fetch = FetchType.EAGER)
#JsonProperty("subagent")
private User parent;
Basically an user contains is parent (who bring him\her into the platform). It works fine. So retrieving an user I can easily retrieve the information of who is its parent (it is contained into the retrieved User object).
Now I need to implement the inverse behavior: I have to define a "query" that starting from a parent retrieve all its children.
The previous User entity class maps the following DB table:
The highlighter parent_id contains the FK that define this recursive relationship. So it contains the PK of another user that is the parent.
I have this UserRepository repository interface (it extents the JpaRepository interface)
public interface UsersRepository extends JpaRepository<User, Integer> {
User findByemail(String email);
List<User> findByUserTypes_TypeName(String typeName);
}
As you can see I am using a "query by method" style. Is it possiblem implement a behavior like this using "query by method" style? (in case also JPQL could be fine)
You can do this
List<User> findByParent_Id(Integer id);
Or you can do this
#Query("SELECT u FROM User u WHERE u.id = ?1")
List<User> getReferredUsers(Integer id);
The relationship between the user and the parent is unidirectional in the given code. By making it bidirectional, it is easy to query the data in either ways.
Refer to below code to make it bidirectional. Also ensure the relevant FetchType to avoid the performance risk. Here FetchType.LAZY is used for one to many association so it queries the data using the proxy reference when needed.
#ManyToOne(fetch = FetchType.EAGER)
#JsonProperty("subagent")
#JsonBackReference
private User parent;
#JsonManagedReference
#OneToMany(fetch = FetchType.LAZY, mappedBy = "parent")
private Set<User> userSet = new HashSet<>();
Child entities are fetched only when parent.getUserSet is used because of the FetchType.Lazy
public Set<User> getUsers(int id) {
User parent = userRepository.getById(id);
return parent.getUserSet();
}
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 getting StackOverflow recursion error when I run query in Postman or Browser .
When i run says:
.w.s.m.s.DefaultHandlerExceptionResolver : Could not write JSON: Infinite recursion (StackOverflowError); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Infinite recursion (StackOverflowError)
Here is the model classes :
#Entity
public class Product {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#NotNull
private String title;
#NotNull
private String description;
#NotNull
private double price;
#OneToOne(fetch = FetchType.LAZY, optional = false)
#JoinColumn(name = "category_id", nullable = false)
private Category category;
private boolean isSealed;
#OneToOne(fetch = FetchType.LAZY, optional = false)
#JoinColumn(name = "currency_id", nullable = false)
private Currency currency;
#OneToOne(fetch = FetchType.LAZY, optional = false)
#JoinColumn(name = "user_id", nullable = false)
private User user;
#Nullable
#OneToMany(mappedBy = "product",
cascade = CascadeType.ALL, orphanRemoval = true)
private List<Images> images;
private Date createdDate = new Date();
#OneToOne(fetch = FetchType.LAZY,
cascade = CascadeType.ALL,
mappedBy = "product")
private View view;
#OneToOne(fetch = FetchType.LAZY,cascade=CascadeType.ALL)
#JoinColumn(name="type_id")
private Type type;
private Long viewCount; }
#Entity public class Images{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String imagePath;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "product_id")
private Product product; }
#Entity public class User implements UserDetails, Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#NotEmpty
private String fullName;
#NotEmpty
#Email
#Column(unique = true)
private String email;
#NotNull
#Column(unique = true)
private int phoneNumber;
#NotEmpty
#Size(min = 5)
private String password;
private Date createAt = new Date();
#Nullable
private String picPath;
#Nullable
private String token;
#ManyToMany
#JoinTable(name = "user_roles", joinColumns = {#JoinColumn(
name = "user_id")},
inverseJoinColumns = {#JoinColumn(name = "role_id")})
private List<Role> roles;
#OneToOne(fetch = FetchType.LAZY,
cascade = CascadeType.ALL,
mappedBy = "user")
private Product product;
#OneToOne(fetch = FetchType.LAZY,
cascade = CascadeType.ALL,
mappedBy = "user")
private View view; }
#Entity
public class Currency{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String code;
private String currency;
private String region_country;
#OneToOne(mappedBy = "currency", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
private Product product; }
#Entity
public class Category {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String imagePath;
#OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY,
mappedBy = "category")
private Product product;
#OneToMany(mappedBy = "category", fetch = FetchType.LAZY,
cascade = CascadeType.ALL)
private Set<Brand> brands; }
#Entity public class Brand {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
#ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinColumn(name = "category_id", nullable = false)
private Category category; }
#Entity public class View {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToOne(fetch = FetchType.LAZY, optional = false)
#JoinColumn(name = "user_id", nullable = false)
private User user;
#OneToOne(fetch = FetchType.LAZY, optional = false)
#JoinColumn(name = "product_id", nullable = false)
private Product product; }
#Entity public class Type {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#NotNull
private String name;
#OneToOne(fetch = FetchType.LAZY,
cascade = CascadeType.ALL,
mappedBy = "type")
private Product product; }
#Id
private String role;
#ManyToMany(mappedBy = "roles")
private List<User> users;
}
More than one of your entities have each other in themselves.
For example, Product has an object of User, and User has an object of Product.
To solve this, you have to write
#JsonBackReference(value = "user-product")
private User user;
in the Product class,
and
#JsonManagedReference(value = "user-product")
private Product product;
In the user class.
Do it in every field and for every class that call each other.
Also, Check this out
JPA: Having lists on both ends without infinite loop
You have cycles in your data model. For example, Product holds Images and Images point back to Products.
This works in an object oriented world, because only pointer references are stored in those fields.
When serialized, however, the actual object is written out as json text. Your Product prints the Images object which in turn prints the Product object which again prints the Image object and so on.
You need to decide how you want to represent your json, map your database model into simple plain old java object and use this for serializations. These POJOs are often called View Model or Transport Objects.
I have oneToOne RelationShip between Employee and student entity i want to fetch all field from Employee Entity and name and modelNumber From Laptop Entity
Employee Entity
public class Employee {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#Column(name = "employee_name")
private String name;
#Column(name = "date_of_birth")
private String dob;
#Column(name = "gender")
private char gender;
#Column(name = "skills")
private String[] skills;
#OneToOne(fetch = FetchType.EAGER, cascade=CascadeType.ALL)
#JoinColumn(name = "laptop_id")
private Laptop laptop;
//getter setter
Laptop Entity
#Entity
public class Laptop {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
private String ram;
private String modelNumber;
private String processor;
//getter Setter
select e.id, e.name, e.dob, e.gender, e.skills,
e.laptop.name, e.laptop.modelNumber
from Employee e
Please start by reading the docs: https://docs.jboss.org/hibernate/orm/5.4/userguide/html_single/Hibernate_User_Guide.html#hql
I want to query data from two tables,
location field in Translation is a foreign key from id field of Location
#Entity
#Table(name = "Translation")
#Data
public class Translation {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#NotNull private String language;
#NotNull private String name;
#NotNull private String description;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "location", nullable = false, insertable = false, updatable = false)
#Fetch(FetchMode.JOIN)
private Location location;
}
#Entity
#Table(name = "Location")
#Data
public class Location {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#NotNull private String code;
#NotNull private String type;
private Double longitude;
private Double latitude;
#Column(name = "parent_id")
private Integer parentId;
#OneToMany(targetEntity = Translation.class, mappedBy="id", fetch = FetchType.EAGER)
private Set<Translation> translations;
}
————————————————————————————————————————
But when I use a query
#Query(
"SELECT new com.afkl.travel.exercise.model.RetrieveLocationResponse("
+ "loc.code, tran.name, loc.type, loc.latitude, loc.longitude, tran.description, loc.parentId)"
+ "FROM Location loc LEFT JOIN loc.translation tran")
List<RetrieveLocationResponse> fetchLeftJoin();
All the fields related to Translation is null, having no idea what happened
UPDATE
The following ones work for me.
#OneToMany(mappedBy = "location", cascade = CascadeType.ALL)
#JsonIgnore
private Set<Translation> translations;
#ManyToOne
#JoinColumn(name = "location")
private Location location;
try
#OneToMany(mappedBy = "location", cascade = CascadeType.ALL)
#JsonIgnore
private Set<Translation> translations;
#ManyToOne
#JoinColumn(name = "location")
private Location location;