JPA去除註釋

Question

所以這是我的設置：

public class Record { 
    //Stuff 
} 

public class RecordNotification { 
    @ What Comes Here? 
    private Record record; 
} 

當我刪除類記錄的對象我想要刪除類RecordNotification包含這個記錄物體爲好。總是有一個RecordNotification類型的對象最多包含相同的Record。記錄不知道RecordNotification。如果RecordNotification被移除，則不會發生任何其他事情。

Answer 1

您必須添加一個屬性到記錄，指向相關的RecordNotification。然後，您可以將其標記爲級聯刪除。就像這樣：

@Entity 
public class Record { 
    @Id 
    private int id; 
    @OneToOne(mappedBy="record", cascade={CascadeType.REMOVE}) 
    private RecordNotification notification; 

    public Record(int id) { 
     this.id = id; 
    } 

    protected Record() {} 
} 

@Entity 
public class RecordNotification { 
    @Id 
    private int id; 
    @OneToOne 
    private Record record; 

    public RecordNotification(int id, Record record) { 
     this.id = id; 
     this.record = record; 
    } 

    protected RecordNotification() {} 
} 

生成的DDL爲：

create table Record (
    id integer not null, 
    primary key (id) 
); 

create table RecordNotification (
    id integer not null, 
    record_id integer, 
    primary key (id) 
); 

alter table RecordNotification 
    add constraint FKE88313FC6EE389C1 
    foreign key (record_id) 
    references Record; 

我已經驗證了這個工程：創建Record和RecordNotification，提交，然後刪除Record並注意到RecordNotification消失。

我用Hibernate 4.1.4.Final。如果這不適用於您，那麼我懷疑EclipseLink中存在錯誤或不當行爲。