java - Hibernate:从带有外键的关联表中删除记录

Question

我是 hibernate 新手。所以，我不知道该怎么做:

我有 3 张 table :

餐 table 人员:

@Entity
@Table(name = "ASD_PERSON")
public class AsdPerson implements Serializable {
    @Id
    @SequenceGenerator(name="seq_name", sequenceName="gen_id_value", allocationSize = 1)
    @GeneratedValue(generator="seq_name")
    @Column(name="F_PERSON_ID", nullable = false)
    private Long fPersonId;

    @OneToMany(mappedBy = "AsdPerson",
               cascade = CascadeType.ALL,
               orphanRemoval = true)
    private List<AsdPersonEvent> asdPersonEventList;

    ... setters and getters ...
}

表事件:

@Entity
@Table(name = "ASD_EVENT")
public class AsdEvent implements Serializable {
    @Id
    @SequenceGenerator(name="seq_name", sequenceName="gen_id_value", allocationSize = 1)
    @GeneratedValue(generator="seq_name")
    @Column(name="F_EVENT_ID", nullable = false)
    private Long fEventId;

    @OneToMany(mappedBy = "AsdEvent",
               cascade = CascadeType.ALL,
               orphanRemoval = true)
    private List<AsdPersonEvent> asdPersonEventList;

    ... setters and getters ...
}

表人员-事件:

@Entity
@Table(name = "ASD_PERSON_EVENT")
@IdClass(AsdPersonEventPK.class)
public class AsdPersonEvent implements Serializable {
    @Id
    @GenericGenerator(name = "generator", strategy = "foreign",
                      parameters = @Parameter(name = "property", value = "asdPerson"))
    @GeneratedValue(generator = "generator")
    @Column(name="F_PERSON_ID", nullable = false, insertable = false,
            updatable = false)
    private Long fPersonId;

    @Id
    @GenericGenerator(name = "generator", strategy = "foreign",
                      parameters = @Parameter(name = "property", value = "asdEvent"))
    @GeneratedValue(generator = "generator")
    @Column(name="F_EVENT_ID", nullable = false, insertable = false,
            updatable = false)
    private Long fEventId;

    @ManyToOne
    @JoinColumn(name = "F_PERSON_ID", insertable = false,
                updatable = false)
    private AsdPerson asdPerson;

    @ManyToOne
    @JoinColumn(name = "F_EVENT_ID", insertable = false,
                updatable = false)
    private AsdEvent asdEvent;

    ... setters and getters ...
}

一切都很完美(添加新记录，创建新对象)，除了当我尝试从事件表或人员表中删除关联记录时的情况:

...
AsdEvent ev = getService().get(115); // get record from Event table by id = 115 (for example)
ev.getAsdPersonEventList().remove(1); // delete some existing records
getService().merge(ev);
...

之后我收到错误:

deleted object would be re-saved by cascade (remove deleted object from associations): [database.AsdPersonEvent#database.AsdPersonEventPK@12908fc]

如何使用注释或其他方式配置 Hibernate 来消除此错误？

Answer 1

如果您有一个复杂的持久实体图，我认为您需要放弃使用orphanRemoval并使用em.remove()手动删除实体。

orphanRemoval 专为简单的父子关系而设计，在这种关系中，如果没有父项，子项就没有意义。如果您的 child 可能有其他关系，也许这不是orphanRemoval的好案例。