与锡耶纳的多重关系

Question

我正在创建一个具有 2 个一对多关系的实体。事件具有"用户"字段和"位置"字段。我正在尝试使用自动查询，但此代码始终返回一个空列表。

    User user = new User("[e-mail]","Maurizio Pozzobon","01","hash","facebook");
    user.insert();
    Place place = new Place("posto","bel posto",null,null);
    place.insert();
    Event e =new Event(user,place, "Festa","Questa è una gran bella festa",null,new Date(),(long) 10,false,null);
    e.insert();
    List<Event> l =user.events.fetch();

事件类是

public class Event extends Model{
    @Id
    public Long id;
    ...
    //Relazioni
    public User user;
    public Place place;
        ...
    public Event(User user, Place place,String nome, String descrizione, String uRLImmagine, Date dataInizio, Long durata, Boolean isRicorrente, Long ricorrenza) {
        this.user=user;
        this.place=place;
        ...
    }
        ...
}

如果我像这样更改事件类

public class Event extends Model{
    @Id
    public Long id;
    ...
    //Relazioni
    public User user;
    //public Place place;
        ...
    public Event(User user, Place place,String nome, String descrizione, String uRLImmagine, Date dataInizio, Long durata, Boolean isRicorrente, Long ricorrenza) {
        this.user=user;
        //this.place=place;
        ...
    }
        ...
}

上面的相同代码返回一个列表，其中包含一个事件（我所期望的）

编辑：这是放置类

public class Place extends Model {

@Id
public Long id;
public String nome;
public String descrizione;
public String uRLImmagine;
public String indirizzo;

//Relazioni
// public User user;
//@Filter("place")
//public Query<Event> events;
private Set<Long> idEvents = new HashSet<Long>();
private Set<Long> idPlaceVotes = new HashSet<Long>();
private Set<Long> idPlaceComments = new HashSet<Long>();

public Place(/*User user,*/ String nome, String descrizione, String uRLImmagine,String indirizzo) {
//  this.user=user;
    this.nome = nome;
    this.descrizione = descrizione;
    this.uRLImmagine = uRLImmagine;
    this.indirizzo = indirizzo;
}

static Query<Place> all() {
    return Model.all(Place.class);
}
public static Place findById(Long id) {
    return all().filter("id", id).get();
}
public String toString() {
    return nome;
}  
public static void delete(Long id) {
    findById(id).delete();
}
}

这是用户类

public class User extends Model {
@Id
public Long id;
public String nome;
public String email;
public String webId;    //ID of the user in the provider website
public String passwordHash;
public String service;
//Relazioni
@Filter("user")
public Query<Event> events;
public User(String email, String name,String webId, String passwordHash, String service) throws Exception {
    if (email!=null)
        this.email=email;
    else
        throw new Exception("An email is required");
    if (name!=null)
        this.nome=name;
    else
        throw new Exception("A name is required");
    if (webId!=null)
        this.webId=webId;
    else
        throw new Exception("A webId is required");
    this.passwordHash=passwordHash;
    this.service = service;
}
public void setEmail(String email) throws Exception{
    if (email!=null)
        this.email=email;
    else
        throw new Exception("An email is needed");
}
static Query<User> all() {
    return Model.all(User.class);
}
public static User findById(Long id) {
    return all().filter("id", id).get();
}
public static User findByEmail(String email){
    return all().filter("email", email).get();
}
public String toString() {
    return nome;
}
}

MyModel是锡耶纳的超级类。模型，但知道它没有任何用处，所以我把它改回了模型。我在播放 1.5 上使用 play-siena 1.1

Answer 1

我发现你的问题:)

这是一个已知问题，但我每次都忘记它。
在您的事件中，只需声明@Column：

public class Event extends Model{
    @Id
    public Long id;
    @Column("user")
    public User user;
    @Column("place")
    public Place place;
}

由于用户和地点都有一个名为"id"的键字段，并且当没有@Column时，Siena 默认使用键字段名称，因此当 GAE 尝试通过字段"id"查找对象时会发生冲突。
我将尝试在 Siena v1.0.0 中纠正此问题（您已经可以在 Play 中透明地使用 siena.jar从 v1.0.0 主干生成

）

问候帕斯卡