CODEWITHSUNDEEP
javahibernatejpa
Eldar Nezametdinov
Eldar Nezametdinov

Reputation: 1925

What correct annotation for this situation. JPA. Hibernate

I would create table, which contains objects. Objects should displayed like columns in table. (+ public, - private)

   +Company
    -int companyId
    -String companyName
    -Set<Department> listOfDepartments = new HashSet<Department>();

    +Department
    -int departmentId
    -String departmentName
    -Set<Worker> listOfWorkers = new HashSet<Worker>();

    +Worker
    -int workerId
    -String workerName

My unsuccessful attempt:

@XmlRootElement(name="Company")
@XmlAccessorType(XmlAccessType.FIELD)
@Entity
@Table(name="Company")
public class Company {
    @Id @GeneratedValue(strategy = GenerationType.AUTO)
    @XmlAttribute (name="id")
    @Column (name="idCompany")
    private int idCompany;

    @XmlElement(name="companyName")
    @Column (name="companyName")
    private String companyName;

    @XmlElement (name = "YYY")
    @ElementCollection
    private Set<Department> listOfDepartments = new HashSet<Department>();

@XmlRootElement(name="Department")
@XmlAccessorType(XmlAccessType.FIELD)
@Entity
@Embeddable
@Table(name="Department")
public class Department {
    @Id @GeneratedValue(strategy = GenerationType.AUTO)
    @XmlAttribute(name="idDepartment")
    @Column (name="idDepartment")
    private int idDepartment;

    @XmlElement(name="departmentName")
    @Column (name="deparmentName")
    private String departmentName;

    @XmlElement (name = "XXX")
    @ElementCollection
    private Set<Worker> listOfWorkers = new HashSet<Worker>();

@XmlRootElement(name="Worker")
@XmlAccessorType(XmlAccessType.FIELD)
@Entity
@Embeddable
@Table(name="Worker")
public class Worker {
    @Id @GeneratedValue(strategy = GenerationType.AUTO)
    @XmlAttribute(name="idWorker")
    @Column (name = "idWorker")
    private int idWorker;

    @XmlElement(name="workerName")
    @Column (name = "workerName")
    private String workerName;

Advise the correct annotation for this situation. I will appreciate.

UPDATE:
companyId|companyName|deptId|deptName|workerId|workerNam|
1|'Lala'|1|'Logical'|1|'Jason'|
1|'Lala'|1|'Logical'|2|'Bason'|
1|'Lala'|2|'Chemical'|1|'Cason'|
1|'Lala'|2|'Chemical'|2|'Dason'|

Upvotes: 0

Views: 1069

Answers (1)

jdev
jdev

Reputation: 5632

If there is some constraint that you want to save all object(entities) in one table in your case company(but the best practice is a normal data base design you should consider company department and workers in separate tables) you have redundancy in data and your table data seems like this...

1 comp1 1 dep1 1 worker1

1 comp1 1 dep1 2 worker2

1 comp1 2 dep2 3 worker3

then correct jpa annotation is:

@XmlAccessorType(XmlAccessType.FIELD)
@Entity
@Table(name="company")
public class Company{
    @Id @GeneratedValue(strategy = GenerationType.AUTO)
    @XmlAttribute(name="idComapny")
    @Column (name="idCompany")
    private int idcompany;

    @XmlElement(name="companyName")
    @Column (name="companyName")
    private String companyName;

   **@Embedded**
   private Department department;

   **@Embedded**
   private Worker worker;//can be removed and put in Department but result is the same
......

and put annotation @Embeddable on top of Department Entity and Worker Entity.

@XmlRootElement(name="Department")
@XmlAccessorType(XmlAccessType.FIELD)
@Entity
@Embeddable
@Table(name="Department")
public class Department {
    @Id @GeneratedValue(strategy = GenerationType.AUTO)
    @XmlAttribute(name="idDepartment")
    @Column (name="idDepartment")
    private int idDepartment;

    @XmlElement(name="departmentName")
    @Column (name="deparmentName")
    private String departmentName;

Upvotes: 4

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