Question

The SchoolClass entity has a composite key made of schoolID, grade and section.
The key in student entity is a composite of userName and schoolID.
I am trying to add two foreign keys of student objects in my SchoolClass. I want to use the same column schoolID in SchoolClass table in all the mappings, am wondering if this is the correct way to do it or not ?

@Entity
public class SchoolClass {

    @Column(unique=true, nullable=false)
    @EmbeddedId
    private SchoolClassPK key;

    @ManyToOne(optional = true)
    @JoinColumns({
        @JoinColumn(name="classRep1", referencedColumnName="userName", nullable = true),
        @JoinColumn(name="schoolID", referencedColumnName="schoolID", nullable = true),
    }) 
    private Student classRep1;

    @ManyToOne(optional = true)
    @JoinColumns({
        @JoinColumn(name="classRep2", referencedColumnName="userName", nullable = true),
        @JoinColumn(name="schoolID", referencedColumnName="schoolID", nullable = true),
    }) 
    private Student classRep2;
......
}

Answer 1

It is a better idea to simply remove composite keys in favor of an auto generated key on the entities involved.