How to map one class with multiple tables in Hibernate/javax.persistance?

Question

I want to use one class to map three tables. I know javax.persistance provides the @SecondaryTable annotation to map two tables to one class.

Below is the code, where I have used @SecondaryTable. It allows me to define only one secondary table. But I need 3 tables to be used by the same class.

@Entity @Table(name = "table1") @SecondaryTable(name="table2") public class TableConfig     implements Serializable {      /**      *       */     private static final long serialVersionUID = 1L;      @Id     @Column(name = "mac", table= "table1")     private String uniqueIdentifier; 

Answer 1

I want to use one class to map three tables, From what I know is that javax.persistance provides @SecondaryTable annotation to map two tables to one class

use @SecondaryTables to map more than one table.

You can map a single entity bean to several tables using the @SecondaryTables class level annotations. To express that a column is in a particular table, use the table parameter of @Column or @JoinColumn.

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for example there is 3 entity's namely: Name , Address & Student:

Name entity will look like:

@Entity @Table(name="name") public class Name implements Serializable {      @Id     @Column(name="id")     private int id;     @Column(name="name")     private String name;      public Name(){}      public Name(int id,String name){         this.id=id;         this.name=name;     }         //getters and setters } 

Address entity will look like:

@Entity @Table(name="address") public class Address implements Serializable {      @Id     @Column(name="id")     private int id;     @Column(name="address")     private String address;      public Address(){}      public Address(int id, String address) {         super();         this.id = id;         this.address = address;     }         //getters and setters } 

Student entity will look like:

@Entity @Table(name="student") @SecondaryTables({     @SecondaryTable(name="name", pkJoinColumns={         @PrimaryKeyJoinColumn(name="id", referencedColumnName="student_id") }),     @SecondaryTable(name="address", pkJoinColumns={         @PrimaryKeyJoinColumn(name="id", referencedColumnName="student_id") }) }) public class Student implements Serializable {      @Id     @Column(name="student_id")     private int studentId;      @Column(table="name")     private String name;      @Column(table="address")     private String address;      public Student(){}      public Student(int studentId){         this.studentId=studentId;     }         //getters and setters } 

Store like:

    Student s= new Student(1);     session.save(s);      Name n=new Name(s.getStudentId(),"Bilal Hasan");     session.save(n);          Address address = new Address(s.getStudentId(), "India");     session.save(address);      Student ob = (Student)session.get(Student.class, s.getStudentId());      System.out.println(ob.getStudentId());     System.out.println(ob.getName());     System.out.println(ob.getAddress()); 

ouput:

1 Bilal Hasan India