使用播放GenericModel进行ManyToOne映射

@Entity
@Table(name=\"trade\")
public class Trade extends GenericModel
{
    @Id
    @Column(name=\"SYB_IDENTITY_COL\", nullable=false, precision=10)
    public long sybIdentityCol;
    @Column(name=\"trade_number\", nullable=false, precision=18)
    public long tradeNumber;
    @Column(name=\"trade_price\", nullable=false, precision=16)
    public double tradePrice;
        .
        .
        .
    @ManyToOne
    @JoinColumn(name=\"book_id\", referencedColumnName=\"SYB_IDENTITY_COL\")
    public Book book;
}
@Entity
@Table(name=\"book\")
public class Book extends GenericModel
 {
        @Id
        @Column(name=\"SYB_IDENTITY_COL\", nullable=false, precision=10)
        public long sybIdentityCol;
        @Column(name=\"book_code\", nullable=false, length=4)
        public String bookCode;
        .
        .
        .
        .
}

       Trade trade = Trade.findById(209115258L);

        Query query = JPA.em().createQuery(\"select b from Trade t, Book b where     t.bookId = b.sybIdentityCol and t.sybIdentityCol=209115258\");
        List<Book> books = query.getResultList();