CODEWITHSUNDEEP
javahibernateforeign-keyscomposite-key
DFL
DFL

Reputation: 173

Hibernate using a foreign key as part of a composite key

Okay, so I have 2 tables on an Oracle DB that I want to represent in Java with Spring 3 and Hibernate 3. They have a Many to One relationship, and the tables are something like

 CAR
 -------
 CAR_PK
 //... other columns

 OPTION
 ------
 CAR_FK
 OPTION_TEXT
 //... other columns

because the Options table is only meaningful with respect to the Car, we only care about accessing it when the Car is accessed, so it doesn't have a unique PK of its own. Furthermore, there can be more than 1 Option per car. Therefore, we are using a composite id of CAR_FK and OPTIONS_TEXT

the java is something like 

 public class Car{
    @Id
    @Column(name="CAR_PK")
    @GeneratedValue(strategy = GenerationType.SEQUENCE,  generator="CAR_KEY_SEQ")
    @SequenceGenerator (name="CAR_KEY_SEQ", sequenceName="CAR_KEY_SEQ", allocationSize=1)
    private long carPk; 

    @OneToMany(cascade= CascadeType.ALL, mappedBy="car")
    @JoinColumn(name="CAR_PK")
    private List<Option> options; 

    //... other stuff
 }

 @IdClass(OptionId.class)
 public class Option{

      @Id
      private long carFk; 

      @Id
      private String optionText; 

      @ManyToOne
      @JoinColumn(name="CAR_FK")
      private Car car; 

      //... other stuff
 }


 @Emeddable
 public class OptionId implements Serializable{

      @Column(CAR_FK)
      private long carFk; 
      @Column(OPTION_TEXT)
      private String optionText
      //... other stuff
 }

On insert, I want the same key generated for carPk in the Car object to be inserted for carFk in the Option object. How do I do this?I get 

 java.sql.SQLException: Invalid column index

What am I doing wrong?

Upvotes: 0

Views: 304

Answers (2)

Biraj B Choudhury
Biraj B Choudhury

Reputation: 684

First thing is since Option has no existence of its own it should not be an Entity. Only Car is an Entity Object whereas Option is a value Object so it should not have any id of its own.

You could change the design as 

 @Entity
 public class Car{
    @Id
    @Column(name="CAR_PK")
    @GeneratedValue(strategy = GenerationType.SEQUENCE,  generator="CAR_KEY_SEQ")
    @SequenceGenerator (name="CAR_KEY_SEQ", sequenceName="CAR_KEY_SEQ", allocationSize=1)
    private long carPk; 

    @Embedded
    private List<Option> options; 

    //... other stuff
 }

@Embeddable
public class Option{
      private String optionText; 

      //... other stuff
 }

That should solve all your problems.

Upvotes: 2

Eric Jeffers
Eric Jeffers

Reputation: 9

You do have a typo in your above code when defining your cascade type: 

@OneToMany(cascase= CascadeType.ALL, mappedBy="car")

This could be causing your Invalid column index.

Upvotes: 1

Related Questions