@Entity
public class Receipt extends Base {

    //other model fields

    @Column(name="email")
    private String Email;

    @ManyToOne
    @JoinColumn(name="store_id")
    private Store Store;

    //getters & setters
}

where.and(q.Email.eq("some@email.com"));

where.and(q.Email.eq("some@email.com")).and(q.Store.id.eq(1));