I have student, test and student_test tables with many-to-many relationship.
Test:
#Entity
#Table(name = "TEST")
public class Test
{
#Id
#Column(name = "TEST_ID")
#GeneratedValue
private Long testId;
#Column(name = "SUBJECT")
private String subject;
#Column(name = "MAX_MARKS")
private String maxMarks;
#Column(name = "MARKS_OBTAINED")
private String marksObtained;
#Column(name = "RESULT")
private String result;
#ManyToMany(fetch = FetchType.LAZY,
mappedBy = "test",
cascade= {CascadeType.PERSIST})
private Set<Student> student = new HashSet<Student>();
}
Student:
#Entity
#Table(name = "STUDENT")
public class Student
{
#Id
#Column(name = "STUDENT_ID")
#GeneratedValue
private Long studentId;
#Column(name = "FIRSTNAME")
private String firstname;
#Column(name = "LASTNAME")
private String lastname;
#Column(name = "EMAIL")
private String email;
#Column(name = "PHONE")
private String phone;
#ManyToMany(cascade = { CascadeType.ALL })
#JoinTable(name = "STUDENT_TEST",
joinColumns = { #JoinColumn(name = "STUDENT_ID", updatable = false) },
inverseJoinColumns = { #JoinColumn(name = "TEST_ID", updatable = false) })
private Set<Test> test = new HashSet<Test>();
}
I have created test record separately.
Now I wanted to insert a Student with relationship record.
The following code is trying to
update student record
update test record
insert a record in relationship table (student_test).
Test test1 = new Test();
test1.setTestId(Long.valueOf("3"));
student1.getTest().add(test1);
student1.setStudentId(Long.valueOf("1"));
try
{
session.saveOrUpdate(student1);
}
catch (HibernateException e)
{
e.printStackTrace();
}
session.getTransaction().commit();
session.close();`
My question is, I need to insert a record into Student and relationship table(student_test) only and it should not update record in test table.
I guess, you forgot to begin transaction. Add following line before saveUpdate
session.getTransaction().begin();
Every thing seems ok except your transaction management.. But I did not see the transaction open in your posted code but you have only transaction commit.. can you make the change and do test again ?
Cheers!
Related
I want to use check constraint to verify if there are more students in the subject more than vacancies. These are the entities:
SubjectOffer
#Entity
#SequenceGenerator(name = "SUBJECT_OFFER_SEQ", sequenceName = "SUBJECT_OFFER_SEQ")
#Table(name = "SUBJECT_OFFER", uniqueConstraints = {
#UniqueConstraint(name = "UQ_SUBJECT_OFFER_COURSE_SUBJECT_SEMESTER_CLASS", columnNames = {"COURSE_ID", "SUBJECT_ID", "SEMESTER", "CLASS_NUMBER"})})
#Check(constraints = "COUNT(STUDENT_SUBJECT_ID) <= VACANCIES")
public class SubjectOffer {
#Id
#GeneratedValue(generator = "SUBJECT_OFFER_SEQ")
#Column(name = "SUBJECT_OFFER_ID", nullable = false)
private Long id;
#OneToMany(fetch = FetchType.LAZY, orphanRemoval = true, cascade = CascadeType.ALL)
#JoinColumn(name = "STUDENT_SUBJECT_ID")
private Set<StudentSubject> studentSubjects = new HashSet<>();
//other attributes
#Column(name = "VACANCIES", nullable = false)
private int vacancies;
}
StudentSubject
#Entity
#Table(name = "STUDENT_SUBJECT")
public class StudentSubject {
#EmbeddedId
private StudentSubjectId id = new StudentSubjectId();
#MapsId("studentId")
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "STUDENT_ID", nullable = false)
private Student student;
#MapsId("subjectOfferId")
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(name = "SUBJECT_OFFER_ID", nullable = false)
private SubjectOffer subjectOffer;
#Column(name = "SEMESTER", nullable = false)
private int semester;
#Column(name = "GRADE")
private BigDecimal grade;
}
I also tried column definition in Set #JoinColumn but it didn't work
SQL check constraints only work on a single table. What you want is a so called SQL assertion constraint, but no database implements that. The best you can do is to pre-create rows for the amount of vacancies and just assign students to these rows without ever creating more rows. This way, you can make sure that you only assign as many students as there are vacancies, given that you use optimistic/pessimistic locking when assigning a student.
I had entity for JSON parsing
#Entity
public class Product{
private int productId;
private String productName;
private BigDecimal productPrice;
private int productVendorId;
private String productVendorName;
private int productCategoryId;
private String productCategoryName;
//getters setters here
created 3 tables in dataBase:
products (product_id, product_name,product_price, product_vendor_id), product_category_id);
vendors(vendor_id, vendor_name); categories (category_id, category_name);
in 1st table product_vendor_id fk -> vendor_id pk in vendors and product_category_id fk -> category_id pk in categories
i tried something like this:
#Entity
#Table(name = "products, schema = "market")
public class Product
#Id
#Column(updatable = false, nullable = false, name = "product_id")
private int Id;
#Column(name = "product_name")
private String productName;
#Column(name = "product_price")
private BigDecimal productPrice;
#Column(name = "product_vendor_id")
private int productVendorId;
#Columnt(table = "vendors", name = "vendor_name")
private String vendor_name;
#Column(name = "product_category_id")
private int productCategoryId;
#Column(table = "categories", name = "category_name")
private String productCategorName;
//getters setters here
received alot of errors: like i have not category_name column in products table etc. this error i received when used
#Table(name = "products", schema = "market" )
#SecondaryTables({#SecondaryTable(name = "vendors", schema = "market"),
#SecondaryTable(name = "categories", schema = "market")})
#JsonIgnoreProperties(ignoreUnknown = true)
public class Product {
....
#JoinColumn(name = "product_vendor_id", referencedColumnName = "vendor_id")
private int productVendorID;
#JoinColumn(table = "vendors", name = "vendor_name")
private String productVendorName;
#JoinColumn(name = "product_category_id", referencedColumnName =
"product_category_id")
private int productCategoryID;
#JoinColumn(table = "categories", name = "category_name")
private String productCategoryName;
exception:
Caused by: org.postgresql.util.PSQLException: ERROR: column
product0_1_.product_id doesn't exist
Hint: There may have been a link to the "product0_.product_id" column
Position: 705
how can i map this entity on 3 tables?
upd: i don't want separate this entity, i need this for deserialize my json object too, just want reuse this entity on different operations.
example of json
{"productID":"1111111","productName":"Cool product","productPrice":"99.99","productVendorName":"Some store","productVendorID":"1337","productCategoryName":"Food","productCategoryID":"1"}
Since there are 3 separate tables, you would want to create three separate entity classes.
Also I'm assuming vendors and category tables will have one to many relation to product.
Try below code:
Product:
#Entity
public class Product {
#Id
private int productId;
private String productName;
private BigDecimal productPrice;
private String productVendorName;
private String productCategoryName;
#ManyToOne
#JoinColumn(name = "productCategoryId")
private Category category;
#ManyToOne
#JoinColumn(name = "productVendorId")
private Vendors vendor;
}
Category:
#Entity
public class Category {
#Id
private Integer categoryId;
private String categoryName;
#OneToMany(mappedBy = "category", cascade = CascadeType.ALL, fetch = FetchType.LAZY, orphanRemoval = true)
#NotEmpty
private List<Product> products = new ArrayList<>();
}
Vendors:
#Entity
public class Vendors {
#Id
private int vendorId;
private String vendorName;
#OneToMany(mappedBy = "vendor", cascade = CascadeType.ALL, fetch = FetchType.LAZY, orphanRemoval = true)
#NotEmpty
private List<Product> products = new ArrayList<>();
}
Though, I would recommend using above approach, if you still want to have single entity class and 3 separate table with redudant data then use below:
#Entity
#SecondaryTables({ #SecondaryTable(name = "vendors"), #SecondaryTable(name = "categories") })
public class Product {
#Id
private int productId;
private String productName;
private BigDecimal productPrice;
private String productVendorName;
private String productCategoryName;
#Column(table = "categories")
private Integer categoryId;
#Column(table = "categories")
private String categoryName;
#Column(table = "vendors")
private int vendorId;
#Column(table = "vendors")
private String vendorName;
}
The id column of the main table will be present in all the 3 tables and used for joining them.
Sorry for poor wording of the question, just didn't know how to explane what i wanted.
All what i need just add #transient annotations for fields which i don't have in products table, and separate it like accepted answer was suggested.
#Entity
#Table(name = "products", schema = "store" )
#JsonIgnoreProperties(ignoreUnknown = true)
public class Product {
#Id
#Column(updatable = false, nullable = false, name = "product_id")
private int productId;
#Column(name = "product_name")
private String productName;
#Column(name = "product_price")
private BigDecimal productPrice;
#Transient
private String productVendorName;
#Transient
private String productCategoryName;
#Transient
private int vendorId;
#Transient
private int categoryId;
#ManyToOne
#JoinColumn(name = "product_category_id")
private Category category;
#ManyToOne
#JoinColumn(name = "product_vendor_id")
private Vendor vendor;
}
for vendors table entity
#Entity
#Table(name = "vendors", schema = "store")
public class Vendor {
#Id
#Column(name = "vendor_id")
private int vendorId;
#Column(name = "vendor_name")
private String vendorName;
#OneToMany(mappedBy = "vendor", cascade = CascadeType.ALL, fetch = FetchType.LAZY,
orphanRemoval = true)
#NotNull
private List<Product> products = new ArrayList<>();
}
and for categories
#Entity
#Table(name = "categories", schema = "store")
public class Category {
#Id
#Column(name = "category_id")
private Integer categoryId;
#Column(name = "category_name")
private String categoryName;
#OneToMany(mappedBy = "category", cascade = CascadeType.ALL, fetch = FetchType.LAZY,
orphanRemoval = true)
#NotNull
private List<Product> products = new ArrayList<>();
}
Wanted to leave here full answer on my question, maybe someone will need it later
Just check some problems with toString. Use it only in Product.class and better make 2 versions for print json and jpa.
Student.java
#Entity
#Table(name = "Student")
#Data
#NoArgsConstructor
public class Student implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#OneToMany(mappedBy = "studentId", cascade = CascadeType.ALL)
private List<Subject> subjectList = new ArrayList<>();
public void addSubject(Subject subject) {
subjectList.add(subject);
subject.setStudentId(this);
}
#Column(name = "firstName")
private String firstName;
#Column(name = "lastName")
private String lastName;
}
Subject.java
#Entity
#Table(name = "Subject")
#Data
#NoArgsConstructor
public class Subject implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name="studentId", nullable = false)
private Student studentId;
#Column(name = "subjectName")
private String subjectName;
#Column(name = "subjectCode")
private int subjectCode;
}
SubjectRepository.java
#Repository
public interface SubjectRepository extends JpaRepository<Subject, Long> {
}
As shown in the code structure above, I have 2 entities (Student, Subject) and a repository class (SubjectRepository). When i try to save into the Subject table, somehow the student name "Thomas" from the Student table gets updated as well in the database. I would like to only insert into Subject table without having any values from the Student table getting updated. Need some help on this. Thanks!
public static void main(String[] args) {
#Autowired protected SubjectRepository subjectRepository;
Student student = new Student();
student.setFirstName("Thomas");
Subject subject = new Subject();
subject.setSubjectName("Chemistry");
subject.setSubjectCode(12345);
student.addSubject(subject)
subjectRepository.save(subject)
}
I would like to only insert into Subject table without having any values from the Student table getting updated
You can achieve this with following code :
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name="studentId", nullable = false, updatable = false)
private Student studentId;
When using Spring JPA I would suggest using the JpaRepository API. You just need to pass in your entity, and it should save as desired.
Ex:
subjectRepository.save(subject);
You have try this
#ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.REFRESH)
#JoinColumn(name="studentId", nullable = false, updatable = false)
private Student studentId;
#MaxExplode You have to use cascade = CascadeType.REFRESH then other details will not update. but if you are try to set updateStudent.setfirstNamr(student.getFirstName()); and then save parent object then i will update. otherwise it will not update.
I have two entities Courses and CourseUser. Courses mapped with OneToMany annotation to a CourseUser. After i add a CourseUser in a list of CourseUsers in Course and update it, new row appears in table CourseUser but it doesn't mapped to a Courses. If i call toString of courseUsers list from courses after update it will be empty.
#Entity
#Table(name = "COURSES")
public class Courses{
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "course_id")
private int course_id;
#Column(name = "course_name", nullable = false)
private String courseName;
#Autowired
#OneToMany(mappedBy = "course", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
private Set<CourseUser> courseUsers = new HashSet<>(0);
CourseUser entity:
#Entity
#Table(name = "COURSE_USERS",
uniqueConstraints = {#UniqueConstraint(columnNames = {"course_name", "user_name"})})
public class CourseUser {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "ev_id")
private int ev_id;
#Column(name = "course_name", nullable = false)
private String courseName;
#Column(name = "user_name", nullable = false)
private String userName;
#Column(name = "course_role")
private String courseRole;
#Column(name = "grade")
private int grade ;
#ManyToOne
#JoinColumn(name = "course_id")
private Courses course;
this is how i add new courseUser to a course :
Courses course = courseDAO.getCourse(id);
Set<CourseUser> courseUsers = course.getCourseUsers();
CourseUser newUser = new CourseUser();
newUser.setUserName(name);
newUser.setCourseRole(role);
newUser.setCourseName(course.getCourseName());
courseUsers.add(newUser);
course.setCourseUsers(courseUsers);
update(course);
and here is CoursesDAO update method:
public void update(Courses course) {
Session session = sf.openSession();
Transaction transaction = session.beginTransaction();
session.merge(course);
session.flush();
transaction.commit();
session.close();
}
At first, you have to save entity, which is referenced by id.
In your case, you have to save CourseUser at first, and then add it to Course.
For example:
Courses course = courseDAO.getCourse(id);
Set<CourseUser> courseUsers = course.getCourseUsers();
CourseUser newUser = new CourseUser();
newUser.setUserName(name);
newUser.setCourseRole(role);
newUser.setCourseName(course.getCourseName());
// this row is very important
// after thus operation newUser will have an id to be referenced
courseUserDto.save(newUser);
courseUsers.add(newUser);
course.setCourseUsers(courseUsers);
update(course);
Also, there is some redundant code that you wrote:
Set<CourseUser> courseUsers = course.getCourseUsers();
// ...
course.setCourseUsers(courseUsers);
course already stores reference to courseUsers.
I'm developing a project which uses BackboneJS in front-end and Java - Spring Core in back-end. I have a problem about mapping entity(domain) objects to DTO objects. I am getting an error message like that :
org.apache.cxf.interceptor.Fault: Infinite recursion (StackOverflowError) (through reference chain: com.countdown.dto.CategoryDTO["countdownList"]->java.util.ArrayList[0]->com.countdown.dto.CountdownDTO["category"]->.......
User.java
#Entity
#Table(name = "Users")
public class User implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "USER_ID", nullable = false)
private int id;
#Column(name = "EMAIL", nullable = false, unique = true)
private String email;
#Column(name = "NAME_SURNAME", nullable = false)
private String nameSurname;
#Column(name = "PASSWORD", nullable = false)
private String password;
#Column(name = "USERNAME", nullable = false, unique = true)
private String username;
#Column(name = "REGISTER_DATE", nullable = false)
private Date registerDate;
#ManyToOne
#JoinColumn(name = "ROLE_ID")
private Role role;
#OneToMany(mappedBy = "createUser")
private List<Countdown> createCountdownList = new ArrayList<Countdown>();
#OneToMany(mappedBy = "updateUser")
private List<Countdown> updateCountdownList = new ArrayList<Countdown>();
#ManyToMany
#JoinTable(name = "FOLLOWINGS",
joinColumns = #JoinColumn(name = "USER_ID"),
inverseJoinColumns = #JoinColumn(name = "COUNTDOWN_ID"))
private List<Countdown> followings = new ArrayList<Countdown>();
//Getters and setters..
}
Role.java
#Entity
public class Role implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "ROLE_ID")
private int id;
#Column(name = "ROLE_NAME", nullable = false)
private String roleName;
#OneToMany(mappedBy = "role",fetch = FetchType.LAZY)
List<User> userList = new ArrayList<User>();
}
Countdown.java
#Entity
#Table(name = "COUNTDOWN")
public class Countdown implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name = "COUNTDOWN_ID")
private int id;
#Column(name = "COUNTDOWN_NAME", nullable = false)
private String countdownName;
#Column(name = "COUNTDOWN_DATE", nullable = false)
private Date countdownDate;
#Column(columnDefinition = "varchar(5000)")
private String countdownDescription;
#JoinColumn(name = "CATEGORY_ID", nullable = false)
#ManyToOne
private Category category;
#JoinColumn(name = "CREATE_USER", nullable = false)
#ManyToOne
private User createUser;
#Column(name = "CREATE_DATE", nullable = false)
private Date createDate;
#JoinColumn(name = "UPDATE_USER", nullable = false)
#ManyToOne
private User updateUser;
#Column(name = "UPDATE_DATE", nullable = false)
private Date updateDate;
#Column(name = "CREATE_USER_IP", nullable = false)
private int createIP;
#ManyToMany
private List<User> followers = new ArrayList<User>();
}
Category.java
#Entity
#Table(name="CATEGORY")
public class Category implements Serializable{
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(name="CATEGORY_ID")
private int id;
#Column(name = "CATEGORY_NAME" , nullable = false)
private String categoryName;
#OneToMany(mappedBy = "category")
private List<Countdown> countdownList = new ArrayList<Countdown>();
}
Business Logic : CategoryServiceImpl.java
I'm getting error in forEach loop.
#Transactional(readOnly = true)
public List<CategoryDTO> getAllCategories() {
List<Category> categoryList;
List<CategoryDTO> categoryDTOList = new ArrayList<CategoryDTO>();
logger.debug("getAllCategories called");
try {
categoryList = categoryDAO.findAll();
for(Category category : categoryList){
categoryDTOList.add(mapper.map(category,CategoryDTO.class));
}
}catch (NoResultException e){
logger.error("getAllCategories method : No Category wasn't found");
logger.warn(e,e);
}catch (Exception e){
logger.error("getAllCategories method : Categories wasn't found");
logger.warn(e,e);
}
return categoryDTOList;
}
Also Do I have to use DTO object in Presentation Layer? Can I use entity objects in presentation layer instead of DTO objects?
How can I solve this problem? Sorry my bad english. Thank you!
Please Try :
#Transactional(readOnly = true)
public List<CategoryDTO> getAllCategories() {
List<Category> categoryList;
List<CategoryDTO> categoryDTOList = new ArrayList<CategoryDTO>();
logger.debug("getAllCategories called");
try {
categoryList = categoryDAO.findAll();
for(Category category : categoryList){
if(category.getCountdownList() != null && !category.getCountdownList().isEmpty()){
for(Countdown countdown : category.getCountdownList()){
countdown.setCategory(null);
}
}
categoryDTOList.add(mapper.map(category,CategoryDTO.class));
}
}catch (NoResultException e){
logger.error("getAllCategories method : Hata: No Category wasn't found");
logger.warn(e,e);
}catch (Exception e){
logger.error("getAllCategories method : Hata: Categories wasn't found");
logger.warn(e,e);
}
return categoryDTOList;
}
For those who are struggling with infinite recursion issue in Dozer.
I use mapId to define a leaf object and stops the recursion.
Let assume we have two entities Course and Teacher, which contains a Many-to-Many relationship, and we want to convert the following object graph to one represented by CourseDTO and TeacherDto. And we hope Dozer stops at the 3rd level.
Teacher 1 ---> m Course 1 ---> m Teacher ---> ...
1st level 2nd level 3rd level
We can first define the following definition for Teacher to TeacherDTO conversion.
This first mapping is used for the root Teacher entity.
Include any other fields you need in the mapping.
mapping(Teacher.class, TeacherDTO.class,
TypeMappingOptions.oneWay()
, mapNull(false)
).fields("courses", "courses");
The following mapping will prevent Dozer from going further to map the contained Course. We define a mapId teacherLeaf for it.
Exclude the fields that cause the infinite recursion. (In my example, it's courses)
Include any other fields you need in the mapping.
mapping(Teacher.class, TeacherDTO.class,
TypeMappingOptions.oneWay(), TypeMappingOptions.mapId("teacherLeaf")
, mapNull(false)
).exclude("courses");
The last one is the mapping rule for Course to courseDTO. The key is that we tell the mapper to use the teacherLeaf mapping rule defined previously to convert the contained Teachers.
mapping(Course.class, CourseDTO.class,
TypeMappingOptions.oneWay()
, mapNull(false)
).fields("teachers", "teachers", useMapId("teacherLeaf"));
Hope this helps!
I use Dozer 6.1.0.