Java – foreign key mapping in the embeddable class

I'm using eclipse link for JPA I have an entity that has a compound key consisting of two fields The following are the fields (members) of my embeddable primary key class

@Embeddable
    public class LeavePK {
       @ManyToOne(optional = false)
       @JoinColumn(name = "staffId",nullable = false)
       private Staff staff;
       @Temporal(TemporalType.TIMESTAMP)
       private Calendar date;
       //setters and getters
    }

My entity will keep leave data related to staff, so I try to combine employee object and departure date to generate composite key Except for my logic, I am not allowed to have a foreign key mapping in the embeddable class When I try to use the JPA tool – > to generate a table from an entity, it gives the following error, which explains, but I don't get it

org.eclipse.persistence.exceptions.ValidationException
Exception Description: The mapping [staff] from the embedded ID class [class rs.stapp.entity.LeavePK] is an invalid mapping for this class. An embeddable class that is used with an embedded ID specification (attribute [leavePK] from the source [class rs.stapp.entity.Leave]) can only contain basic mappings. Either remove the non basic mapping or change the embedded ID specification on the source to be embedded.

Does that mean I can't have a key (compound key), it's also a foreign key Is there any way to complete this enterprise risk management? Please help. thank you

Solution

Do not put the relationship into the ID class, which is neither @ IdClass nor @ embeddedid@ An embeddable class can only contain @ basic, @ column, @ temporary, @ enumerated, @ lob, or @ embedded comments Everything is provider specific syntax (for example, hibernate allows this, but since you are using JPA RI's eclipse link, I suspect this is what you want)

The following is an example of JPA PK / FK mapping:

@Entity
@Table(name = "Zips")
public class Zip implements Serializable
{
    @EmbeddedId
    private ZipId embeddedId;

    @ManyToOne
    @JoinColumn(name = "country_code",referencedColumnName = "iso_code")
    private Country country = null;

    ...
}

@Embeddable
public class ZipId implements Serializable
{
    @Column(name = "country_code")
    private String countryCode;

    @Column(name = "code")
    private String code;

    ...
}

HTH