CODEWITHSUNDEEP
javasqldatabasehibernate
Amer M.
Amer M.

Reputation: 68

Hibernate: Multiple tables, same object

I am trying to write a simple app that contains one table that keeps track of payments each user has made and a second table that contains total amount each user has paid (sum of all payments). Currently, both tables have the same fields (firstName, lastName, amount) and I have mapped them from the same Java class and I have trouble mapping that class to multiple tables. Is there any simple solution to this?

@Entity
@Table(name="Payment")
public class Payment{

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Long id;

  @Column
  @NotNull
  private String firstNname;

  @Column
  @NotNull
  private String lastNname;

  @Column
  @NotNull
  private double amount;

... Constructor, getters and setters
}

Upvotes: 2

Views: 1588

Answers (3)

SternK
SternK

Reputation: 13041

You can try to use @SecondaryTable annotation.

Something like this:

@Entity
@Table(name = "MY_PAYMENT")
@SecondaryTable(name = "MY_PAYMENT_DETAILS",
    pkJoinColumns = @PrimaryKeyJoinColumn(name = "pd_payment_id"))
public class Payment {

   @Id
   @Column(name = "p_id")
   private Long id;
   
   @Column(name = "p_first_name")
   private String firstNname;

   // ...
   
   @Column(name = "pd_amount", table = "MY_PAYMENT_DETAILS")
   private double amount;
}

This is assumed that you have the following schema:

create table MY_PAYMENT
(
   p_id number,
   p_first_name varchar(200),
   CONSTRAINT MY_PAYMENT_PK PRIMARY KEY(p_id)
);

create table MY_PAYMENT_DETAILS
(
   pd_payment_id number,
   pd_amount number,
   CONSTRAINT MY_PAYMENT_DETAILS_PK PRIMARY KEY(pd_payment_id),
   CONSTRAINT MY_PAYMENT_DETAILS_FK foreign key(pd_payment_id) references MY_PAYMENT(p_id)
);

See also this section of hibernate documentation.

Upvotes: 1

Zurahid Omeragić
Zurahid Omeragić

Reputation: 11

You should go with @MappedSuperclass. It's the easiest choice for you.

Upvotes: 1

Pablo Fradua
Pablo Fradua

Reputation: 389

You need:

@MappedSuperclass public class ClassWithTheFields{ \\Not annotated with @Entity @Id private Integer Id; ... }

@Entity public class EntityClass extends ClassWithTheFields{}

@Entity public class AnotherEntityClass extends ClassWithTheFields{}

This way, both classes extending ClassWithTheFields will have the same fields, but will be mapping different tables.

You just need to put all the common fields in a class annotated with @MappedSuperclass, but not@Entity, and then extend this class in other classes annotated with @Entity.

Upvotes: 1

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