无法初始化集合

Question

我有recs模型映射到postgresql中的recs表，一些字段被声明为Set，当我运行代码时，它将错误抛出：

org.hibernate.exception.SQLGrammarException: could not initialize a collection: Recs._recsDetailName
caused by: org.postgresql.util.PSQLException: ERROR: relation "recs__recsdetailname" does not exist

我的recs模型：

@Entity
@Table(name = "RECS", uniqueConstraints = @UniqueConstraint(columnNames = "id"))
public class Recs implements Serializable, Cloneable {

    /**
     * Serialized version unique identifier.
     */
    private static final long serialVersionUID = -7316874431882307750L;

    @Id
    @Column(name = "id")
    private int _id;

    @Basic
    @Column(name = "recs_num")
    private int _recsNum;

    @Basic
    @Column(name = "details")
    private String _details;

    @Column(name = "d_stamp")
    private Date _timeStamp;

    @ElementCollection(fetch = FetchType.EAGER) 
    @Column(name = "recs_detail_name")
    private Set<String> _recsDetailName;

    ..

我的桌子：

        Column         |            Type             |  Modifiers                           
-----------------------+-----------------------------+-------------------------------
 id                    | integer                     | not null default 
 recs                  | xml                         | 
 recs_num              | integer                     | 
 details               | character varying(300)      | 
 d_stamp               | timestamp without time zone | default now()
 recs_detail_name      | text[]                   

|

db中的示例recs_detail_name如下所示：

{"TeleNav GPS Navigator","Photobucket for BlackBerry","Cellfire Mobile Coupons"}

谁知道什么可能是错的???感谢

Answer 1

ElementCollection未映射到将序列化集合的单个列。它使用一个附加表进行映射，该表包含String（recs_detail_name）的列和引用拥有表的主键的外键列。这当然在hibernate documentation中描述。

如果要将Set映射到单个列，则必须使用自定义用户类型。