Hibernate爲新的子實體生成ghost條目

我對Hibernate有一個奇怪的問題（對我來說），這是我無法理解的。下面的代碼是我在使用與案例是我聚合根額外的實體CaseToSuggestion實體案例和建議之間的屬性建模多對一關係的嘗試：Hibernate爲新的子實體生成ghost條目

@Entity 
@Table(name = "sga_cases") 
public class Case { 

    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private int id; 

    // Business key 
    @Column(name = "caseid", unique = true, nullable = false) 
    private String caseId; 

    ... 

    @OneToMany(mappedBy = "associatedCase", orphanRemoval = true, cascade = CascadeType.ALL) 
    private Set<CaseToSuggestion> associatedSuggestions = new HashSet<CaseToSuggestion>(); 

    ... 
} 


@Entity 
@Table(name = "sga_suggestions") 
public class Suggestion { 

    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private int id; 

    @Column(name = "suggestionid", unique = true, nullable = false) 
    private String suggestionId; 

    @Column(name = "localizationkey", nullable = false) 
    private String localizationKey; 

    @OneToMany(mappedBy = "associatedSuggestion", orphanRemoval = true, cascade = CascadeType.ALL) 
    private Set<CaseToSuggestion> caseMapping = new HashSet<CaseToSuggestion>(); 

    ... 
} 


@Entity 
@Table(name = "sga_case2suggestion") 
public class CaseToSuggestion { 

    @Id 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private int id; 

    @Column(name = "feedback") 
    private float feedback; 

    @ManyToOne 
    @JoinColumn(name = "caseid") 
    private Case associatedCase; 

    @ManyToOne(cascade = CascadeType.ALL) 
    @JoinColumn(name = "suggestionid") 
    private Suggestion associatedSuggestion; 

    ... 
}

如果我創建上述實體的新對象，設置相應的關聯，然後存儲它們與EntityManager的一切工作正常：

Case c = new Case(...) 
Suggestion sugg = new Suggestion(...); 
CaseToSuggestion case2sugg = new CaseToSuggestion(c, sugg, 1.0f); 

c.getAssociatedSuggestions().add(case2sugg); 
sugg.getAssociatedCases().add(case2sugg);

通過entityManager.persist(c);

其次如果我想添加一個新的ASSO ciation的案例已在我檢索案例和建議實體我想從EntityManager的關聯，並將它們添加到一個新的CaseToSuggestion數據庫：

CaseToSuggestion c2s = new CaseToSuggestion(c, s, fb); 
c.getAssociatedSuggestions().add(c2s); 
s.getAssociatedCases().add(c2s);

其次entityManager.merge(c);

的的CaseToSuggestion實體存儲在數據庫中，但對於每一個進入我得到一個「鬼條目」用新生成的ID和各個領域空：

+----+----------+--------+--------------+ 
| id | feedback | caseid | suggestionid | 
+----+----------+--------+--------------+ 
| 3 |  1 |  3 |   1 | 
| 4 |  1 |  4 |   2 | 
| 5 |  1 |  5 |   2 | 
| 6 |  0 | NULL |   NULL | 
| 7 |  1 |  6 |   2 | 
| 8 |  0 | NULL |   NULL | 
| 9 |  1 |  7 |   2 | 
| 10 |  0 | NULL |   NULL | 
+----+----------+--------+--------------+

沒有任何人有一個想法是什麼可能會導致這樣？

來源

2012-11-13 fiendie

什麼是一個漂亮的第一個問題（嚴重） – Sheena

我認爲這個問題可能出現在級聯中，試着只保留聚合根下的級聯從Case-CaseToSuggestion-> Suggestion'的依賴樹，然後刪除級聯那是在另一個方向。 – Augusto

感謝您的提示。我在「建議」中刪除了級聯，但不幸的是問題仍然存在。 – fiendie

好的，我明白了。刪除建議中的OneToMany-Mapping完全解決了我的問題。

來源

2012-11-13 16:31:16 fiendie

Hibernate爲新的子實體生成ghost條目

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