Hi,

I'm using Hibernate with annotations (in spring), and I have an object which has an ordered, many-to-one relationship which a child object which has a composite primary key, one component of which is a foreign key back to the id of the parent object.

The structure looks something like this:

+=============+                 +================+
| ParentObj   |                 | ObjectChild    |
+-------------+ 1          0..* +----------------+
| id (pk)     |-----------------| parentId       |
| ...         |                 | name           |
+=============+                 | pos            |
                                | ...            |
                                +================+

I've tried a variety of combinations of annotations, none of which seem to work. This is the closest I've been able to come up with:

@Entity
public class ParentObject {
    @Column(nullable=false, updatable=false)
    private String id;

    @OneToMany(mappedBy="object", fetch=FetchType.EAGER)
    @IndexColumn(name = "pos", base=0)
    private List<ObjectChild> attrs;

    ...
}

@Entity
public class ChildObject {
    @Embeddable
    public static class Pk implements Serializable {
        @Column(nullable=false, updatable=false)
        private String objectId;

        @Column(nullable=false, updatable=false)
        private String name;

        @Column(nullable=false, updatable=false)
        private int pos;

        ...
    }

    @EmbeddedId
    private Pk pk;

    @ManyToOne
    @JoinColumn(name="parentId")
    private ParentObject parent;

    ...
}

I arrived at this after a long bout of experimentation in which most of my other attempts yielded entities which hibernate couldn't even load for various reasons.

The error I get when I try to read one of these objects (they seem to save OK), I get an error of this form:

org.hibernate.exception.SQLGrammarException: could not initialize a collection: ...

And the root cause is this:

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'attrs0_.id' in 'field list'

I'm sure I'm missing something simple, but the documentation is not clear on this matter, and I haven't been able to find any examples of this anywhere else.

Thanks!