I'm trying to achieve something like sql command below by using HQL and JPA.
Instead of "SELECT user_id..." I need SELECT OBJECT(o).
SELECT user_id FROM posix_user o INNER JOIN postgre_user n ON n.id=o.user_id WHERE n.name='USERNAME2'
I have some problems with this part of the code in JPA DAO:
public List<PosixUserEntity> listPosixUsers(final String uid_number) {
final StringBuilder queryString = new StringBuilder("SELECT OBJECT(o) FROM ");
queryString.append(this.entityClass.getSimpleName());
queryString.append(" o JOIN com.services.dao.user.jpa.UserEntity n ON (n.id=o.user_id) WHERE n.name LIKE :uid_number");
final Query findByNameQuery = entityManager.createQuery(queryString.toString()).setParameter("uid_number", uid_number);
return findByNameQuery.getResultList();
}
JOIN ON is not allowet here and I did not know how to replace it.
Also how can I replace com.services.dao.user.jpa.UserEntity by something cleaner.
There is my Entites, they may need to be improved:
#Entity
#Table(name = "posix_user")
public class PosixUserEntity implements Serializable {
private static final long serialVersionUID = 1L;
#Id
//#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "user_id")
private String user_id;
#Column(name = "uid_number")
private String uid_number;
#Column(name = "home_directory")
private String home_directory;
#Column(name = "login_shell")
private String login_shell;
#Column(name = "group_id")
private String group_id;
//getters,setters....
#Entity
#Table(name = "postgre_user")
#SQLDelete(sql = "update postgre_user set status = 'removed' where id = ?")
public class UserEntity implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "name", unique = true, nullable = false)
private String name;
#Column(name = "password")
private String password;
#Enumerated(EnumType.STRING)
#Column(name = "status")
private UserStatus status;
#Column(name = "firstname")
private String firstName;
#Column(name = "lastname")
private String lastName;
#Column(name = "email")
private String email;
#Column(name = "usertype")
private String userType;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "user")
private List<UserRoleTargetGroupEntity> userRoleTargetGroupEntity;
#Column(name = "last_login")
private String lastLogin;
#Column(name = "previous_login")
private String previousLogin;
#JsonIgnore
#Column(name = "change_password_flag")
private Boolean userPasswordResetFlag;
#OneToOne(cascade=CascadeType.ALL)
#PrimaryKeyJoinColumn
private PosixUserEntity posixUserEntity;
You may also need to know that FOREIGN KEY (user_id) REFERENCES postgre_user (id) - it should look like that
Can you know how can I modify my SELECT?
I've tested a simplified version of your classes
#Entity
#Table(name = "posix_user")
public class PosixUserEntity {
#Id
#Column(name = "user_id")
private Long user_id;
// getter + setter
}
#Entity
#Table(name = "postgre_user")
public class UserEntity {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
#OneToOne(cascade=CascadeType.ALL)
#PrimaryKeyJoinColumn
private PosixUser posixUserEntity;
// getter + setter
}
And this JPQL query works as expected
String jpql = "SELECT p "
+ "FROM UserEntity n JOIN n.posixUserEntity p "
+ "WHERE n.name LIKE :uid_number)";
JOIN is allowed because you have mapped the relationship in UserEntity.
and you don't need to specify the complete name of your entity class.
Check if it has been included when you define your persistence unit.
Hope this helps.
Related
Here are my entity classes.
JobPost.java
#Entity
#Table(name = "job_post")
public class JobPost {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "job_post_id")
private Long jobPostId;
#Column(name = "job_title")
private String jobTitle;
#Column(name = "job_description")
private String jobDescription;
#Column(name = "vacancy")
private int vacancy;
#Column(name = "posted_date")
#JsonFormat(pattern = "yyyy-MM-dd")
private Date postedDate;
#Column(name = "total_applicants")
private int totalApplicants;
}
JobApplication.java
#Entity
#Table(name = "job_application")
public class JobApplication {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "job_application_id")
private Long jobApplicationId;
#Column(name = "job_post_id")
private Long jobPostId;
#Column(name = "applicant_id")
private Long applicantId;
}
Applicant.java
#Entity
#Table(name = "applicant")
public class Applicant {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "applicant_id")
private Long applicantId;
#Column(name = "applicant_name")
private String applicantName;
#Column(name = "applicant_mobile_no")
private String applicantMobileNo;
#Column(name = "applicant_email")
private String applicantEmail;
}
My main goal is to listing the ApplicantList on JobPostId. I am totally new in Spring data JPA. Is JPA mappings are correct?. I don't know which query I should fire in order to fetch the applicantList based on jobPostId.
I would recommend to use JpaMappings and use SpringData instead of using native query.
Steps to follow:
Many-To-Many:
Use JoinTable to directly map JobPost and Applicant instead of creating a separate class.
Link for help:
https://attacomsian.com/blog/spring-data-jpa-many-to-many-mapping
Use SpringData JPA findOne or findById method (depends on spring version). If you use EAGER fetch then it will give you all Applicants associated with the JobPost Id.
One-To-Many
Keep JobApplication class and use OneToMany annotation.
Link for help:
https://attacomsian.com/blog/spring-data-jpa-one-to-many-mapping
Query:
#Query("select a from JobPost j inner join j.jobApplicantList ja inner join ja.applicant a where j.jobPostId=:jobPostId")
List<String> findAllJobApplicants(#Param("jobPostId") Long jobPostId);
I think that you should configure the mappings in such a way.To do this, you only need two entities
JobPost.java
#Entity
#Table(name = "job_post")
public class JobPost {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "job_title")
private String jobTitle;
#Column(name = "job_description")
private String jobDescription;
#Column(name = "vacancy")
private int vacancy;
#Column(name = "posted_date")
#JsonFormat(pattern = "yyyy-MM-dd")
private Date postedDate;
#Column(name = "total_applicants")
private int totalApplicants;
#ManyToMany
#JoinTable(name = "applicant_job_post",
joinColumns = {
#JoinColumn(name = "job_post_id", referencedColumnName = "id")
}, inverseJoinColumns = {
#JoinColumn(name = "applicant_id", referencedColumnName = "id")
})
private Set<Applicant> applicants;
public JobPost() {
}
public void addApplicant(Applicant applicant) {
applicants.add(applicant);
applicant.getJobPosts().add(this);
}
public void removeApplicant(Applicant applicant) {
applicants.remove(applicant);
applicant.getJobPosts().remove(this);
}
}
Applicant.java
#Entity
#Table(name = "applicant")
public class Applicant {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
#Column(name = "applicant_name")
private String applicantName;
#Column(name = "applicant_mobile_no")
private String applicantMobileNo;
#Column(name = "applicant_email")
private String applicantEmail;
#ManyToMany(mappedBy = "applicants")
private Set<JobPost> jobPosts;
public Applicant() {
}
public void addJobPost(JobPost jobPost) {
jobPosts.add(jobPost);
jobPost.getApplicants().add(this);
}
public void removeJobPost(JobPost jobPost) {
jobPosts.remove(jobPost);
jobPost.getApplicants().remove(this);
}
}
Is there a way to join two tables in Spring JPA without using association class.
I have two MySQL DB tables :
employees(id,.....,department_id)
departments(id,.....)
And I'm searching for a way to join these tables using only my employee and department classes.
Currently, I managed to join two tables but with the third association class.
My current implementation is:
Employee class:
#Entity(name = "Employee")
#Table(name = "employees")
#JsonInclude(Include.NON_NULL)
public class Employee implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#JsonIgnore
#Column(name = "employee_id")
private Long employeeId;
#Column(name = "first_name")
private String firstName;
#Column(name = "last_name")
private String lastName;
#Column(name = "phone_number")
private String phoneNumber;
#Column(name = "hire_date")
private Double hireDate;
#Column(name = "job_id")
private Long jobId;
#Column(name = "salary")
private Double salary;
#Column(name = "commission_pct")
private Double commissionPct;
#Column(name = "employees")
private Long employees;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(name = "id", insertable = false, updatable = false)
#Fetch(FetchMode.JOIN)
private Department department;
}
Department class:
#Entity(name = "Department")
#Table(name = "departments")
#JsonInclude(Include.NON_NULL)
public class Department implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "department_name")
private String departmentName;
#Column(name = "department_id")
private long departmentId;
#Column(name = "manager_id")
private Double managerId;
#Column(name = "location_id")
private Double locationId;
}
Association class:
public class DeptEmpDto {
private long departmentId;
private String departmentName;
private Double managerId;
private Double locationId;
private long employeeId;
private String firstName;
private String lastName;
private String phoneNumber;
private Double hireDate;
private Long jobId;
private Double salary;
private Double commissionPct;
}
Repository:
public interface IEmployeeRepository extends JpaRepository<Employee, Long> {
#Query("SELECT new com.concretepage.entity.DeptEmpDto(d.departmentId,d.departmentName,d.managerId,d.locationId,e.employeeId,e.firstName,e.lastName,e.phoneNumber,e.hireDate,e.jobId,e.salary,e.commissionPct FROM Employee e INNER JOIN Department d ON d.id = e.jobId")
List<DeptEmpDto> fetchEmpDeptDataInnerJoin();
You can use it in Employee class
#ManyToMany(fetch = FetchType.EAGER)
#JoinTable(
name = "DeptEmp",
joinColumns = #JoinColumn(name = "emp_id",referencedColumnName = "id"),
inverseJoinColumns = #JoinColumn(name = "dep_id",referencedColumnName = "id")
)
private Set<Departments> departments = new HashSet<>();
Look at this about JPA
Logically an employee can't work in two departements so your relationship is correct
But you can do that with a #ManyToMany annotation.
I'm just learning Spring Data. I want to map a database view Entity with a simple Entity and pass to DTO which will contain columns both entities. I understand that I can use a special database view but I need to map precisely entities of Spring Data.
I have a database view Entity "MentorStudents":
#Entity
#Table(name = "mentor_students")
#Immutable
public class MentorStudents implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#Column(name = "mentor_id", updatable = false, nullable = false)
private Long mentorId;
//This entity I need to map
private Mentor mentor;
#Column(name = "active_students")
private Integer activeStudents;
public MentorStudents() {
}
//getters, setters, equals, hashCode
}
A database view sql of an above entity is:
SELECT id AS mentor_id, active_students
FROM mentor
LEFT JOIN ( SELECT mentor_id, count(mentor_id) AS active_students
FROM contract
WHERE close_type IS NULL
GROUP BY mentor_id) active ON mentor.id = active.mentor_id
ORDER BY mentor.id;
And I have a simple Entity "Mentor":
#Entity
#Table(name = "mentor")
#Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class Mentor implements Serializable {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGenerator")
#SequenceGenerator(name = "sequenceGenerator")
private Long id;
#NotNull
#Column(name = "first_name", nullable = false)
private String firstName;
#NotNull
#Column(name = "last_name", nullable = false)
private String lastName;
#Column(name = "patronymic")
private String patronymic;
#Column(name = "phone")
private String phone;
#NotNull
#Column(name = "email", nullable = false)
private String email;
#Column(name = "skype")
private String skype;
#Column(name = "country")
private String country;
#Column(name = "city")
private String city;
#Column(name = "max_students")
private Long maxStudents;
//getters, setters, equals, hashCode
I have to get a DTO which contains all Mentor fields and an "activeStudents" MentorStudents field without a "mentorId" field. How do it?
Use spring data projection:
public interface YourDto {
// all Mentor get fields
String getFirstName();
...
// activeStudents get field
Integer getActiveStudents();
}
public interface YourRepository extends JpaRepository<YourEntity, Integer> {
#Query(value = "select ...(all fields match YourDto) from Mentor m, MentorStudents s where m.id = s.mentorId and m.id = ?1")
Optional<YourDto> findMyDto(Integer mentorId);
}
I am looking to create a DAO which represents a join of two tables with Java Hibernate. Here is the SQL I'd like to represent (Postgres 9.6 incase that matters):
SELECT tableOneValue, tableTwoValue
FROM table_one, table_two
WHERE table_one_filter = 2 AND table_one_id = table_two_id;
These tables have a OneToOne relationship.
Table1.java
#Entity
#Data
#Table(name="table_one")
public class TableOneDao implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "table_one_id")
private int tableOneId;
#Column(name = "table_one_value")
private String tableOneValue;
#Column(name = "table_one_filter")
private int tableOneFilter;
}
Table2.java
#Entity
#Data
#Table(name="table_two")
public class TableTwoDao implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "table_twp_id")
private int tableTwpId;
#Column(name = "table_two_value")
private String tableTwoValue;
}
I'm very new to hibernate so maybe this isn't the right way to think with it. What I would love to do is define a SomeDao class where I can do: daoManager.findAll(SomeDao.class, Pair.of("tableOneFilter", 2));
This would return a List<SomeDao> where we get all the rows that satisfy tableOneFilter == 2.
You need to use the #OneToOne and #JoinColumn annotation.
Pay special attention to the userDetail attribute mapping.
For example, the user class:
#Entity
#Table(name = "USERS")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "USR_ID")
private long id;
#Column(name = "USERNAME", nullable = false, unique = true)
private String username;
#Column(name = "PASSWORD")
private String password;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name="USR_DET_ID")
private UserDetail userDetail;
// Add Constructor, Setter and Getter methods
}
And this user details class:
#Entity
#Table(name = "USER_DETAILS")
public class UserDetail {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "USR_DET_ID")
private long id;
#Column(name = "FIRST_NAME")
private String firstName;
#Column(name = "LAST_NAME")
private String lastName;
#Column(name = "EMAIL")
private String email;
#Column(name = "DBO")
private LocalDate dob;
// Add Constructor, Setter and Getter methods
}
Check the full code here.
Here is a JPA query which will work with your existing entity structure with the latest version of hibernate.
SELECT t1.tableOneValue, t2.tableTwoValue
FROM TableOneDao AS t1 JOIN TableTwoDao AS t2 ON t1.table_one_id = t2.table_two_id
WHERE t1.table_one_filter = ?
You can write a JPQL statement which is much better. Here is the sample solution:
SELECT NEW com.test.package.dao(t1.valueOne, t2.valueTwo)
FROM table_one t1 JOIN table_two t2
WHERE t1.filter = 2 AND t1.id = t2.id;
Please refer to this link and jump to the section where it mentions Result Classes (Constructor Expressions). Hope it helps. Thanks.
I am using hibernate criteria query framework for generating reports. I have to provide sorting and filtering as well. Things were working fine when the data was confined to a single entity. However I have a requirement to join multiple entities and show the result in a single table. Following are the entities:
#Entity
#Table(name = "user_profile")
#Where(clause = "deleted = 0")
public class UserProfile {
#GeneratedValue(strategy = GenerationType.AUTO)
Long id;
#Column(name = "username")
private String username;
#Column(name = "email")
private String email;
#Column(name = "first_name")
private String firstName;
#Column(name = "middle_name")
private String middleName;
#Column(name = "last_name")
private String lastName;
}
#Entity
#Table(name = "user_data")
public class UserData {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#Column(name = "username")
private String username;
#Column(name = "password")
private String password;
#Column(name = "account_nonexpired")
private Boolean accountNonExpired = true;
#Column(name = "account_nonlocked")
private Boolean accountNonLocked = true;
#Column(name = "credentials_nonexpired")
private Boolean credentialsNonExpired = true;
#Column(name = "enabled")
private Boolean enabled = false;
}
#Entity
#Table(name = "user_role")
public class Role {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
#Column(name = "username")
private String username;
#Column(name = "role")
private String role;
}
These entities have a common user name. Is it possible to create an entity which has no table but just contains these entities as fields? For eg:
public Class UserDataProfileRoleMapping{
private UserProfile userProfile;
private List<Role> role;
private UserData userData;
}
I can create a mapping table but I was keeping it as a last resort.
Edit
The query which I want to fire is something like:
select * from user_data u, user_role r, user_profile up
where
u.username = r.username and
r.username = up.username;
You should create a POJO as a DTO which will hold exactly the information you need and use that instead of the actual entities. Let's assume we have three entities, Order, OrderItem and Customer and the query should be something like
SELECT Order.orderDate, Customer.name, OrderItem.amount
FROM Order
JOIN Customer ON Order.customerId = Customer.id
JOIN OrderItem ON Order.id = OrderItem.orderId
WHERE OrderItem.name = 'Puppet';
Now, the DTO would be:
public class ReturnDto {
private Date date;
private String customerName;
private int amount;
public ReturnDto(Date date, String customerName, int amount) {
this.date = date;
...
}
// getters for the three properties
}
And in your DAO you could do something along the following lines:
CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
CriteriaQuery<ReturnDto> cQuery = cb.createQuery(ReturnDto.class);
Root<Order> orderRoot = cQuery.from(Order.class);
Join<Order, Customer> customerJoin = orderRoot.join(Order_.customer);
Join<Order, OrderItem> orderItemJoin = orderRoot.join(Order_.orderItems);
List<Predicate> criteria = new ArrayList<Predicate>();
criteria.add(cb.equal(orderItemJoin.get(OrderItem_.name), "Puppet");
// here you can do the sorting, e.g. - all with the criteria API!
cQuery.orderBy(...);
cQuery.distinct(true);
cQuery.select(cb.construct(ReturnDto.class,
orderRoot.get(Order_.date),
customerJoin.get(Customer_.name),
orderItemJoin.get(OrderItem_.amount)
));
cQuery.where(cb.and(criteria.toArray(new Predicate[criteria.size()])));
List<ReturnDto> returnList = entityManager.createQuery(cQuery).getResultList();
Obviously, you cannot save the items in the returned list, but you get exactly the information you want and you can still handle things with the list, which you cannot handle with SQL/Criteria API.
Update: Just found this link, which may also help with the concept I used above: http://www.javacodegeeks.com/2013/04/jpa-2-0-criteria-query-with-hibernate.html?utm_content=buffer0bd84&utm_source=buffer&utm_medium=twitter&utm_campaign=Buffer