我正在尝试在Hibernate 4.3.5 /
JPA2对象中使用orphanRemoval，但它似乎没有按我预期的那样工作。但是，我不确定我做错了什么，还是Hibernate中的错误。

鉴于以下关系（为简便起见，省略了@ Version，getter和setter）：

@Entity
public class Provider implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private Long id;

    private String name;

    @OneToMany(orphanRemoval=true,cascade=CascadeType.REMOVE)
    @JoinColumn(name="provider_id", referencedColumnName="id")
    private List<Contract> contracts;
}


@Entity
public class Contract implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private Long id;

    private String volume;

    @OneToMany(orphanRemoval=true,cascade=CascadeType.REMOVE) // delete any attachments that were previously uploaded with this contract
    @JoinTable(name="contract_attachment", joinColumns = @JoinColumn(name = "contract_id", referencedColumnName = "id"), inverseJoinColumns = @JoinColumn(name = "attachment_id", referencedColumnName = "id"))
    private List<Attachment> attachments;
}

@Entity
public class Attachment implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private Long id;

    private String filename;
}

我希望，如果我从Provider.contracts列表中删除合同，那么它将从合同表中删除相应的行，并从附件表中删除所有相关的附件。但是，只有合同表被删除。附件表未修改。

例如：

    // loop over all contracts and delete the one with the matching id
    for(Iterator<Contract> it = provider.getContracts().iterator(); it.hasNext();){
        Contract c = it.next();
        if( c.getId() == contractId ){
            it.remove();
            break;
        }
    }

鉴于附件是相对于“合同”表的ManyToOne，如果删除了“合同”，则附件将被孤立。但是即使使用orphanRemoval=true，也不会从数据库中删除行。

我发现了一些与Hibernate 3有关的问题（都在SO，Jira和其他在线站点上），但是我已经了解到它在Hibernate4中已得到解决。但是在使用Hibernate4.3.5时，我仍然看到此问题。从此问题开始，它似乎可以正常工作，因此我不确定为什么无法使其正常运行。

我的代码中是否有错误/缺失，还是Hibernate仍然有问题？我是否需要实现equals并hashCode在任何这些实体类中orphanRemoval正常工作？我尝试在“合同”和“附件”中实现这两种方法，但没有区别。

查看Hibernate日志，它显示Hibernate对联接表（或FK映射）进行了更改，但实际上并未从关联表中删除该行。我可以看到Hibernate在Contract表中设置了provider_id= null，但是它不应该删除Contract行吗？

2014-07-04 15:06:41,333 [main] [-] DEBUG org.hibernate.SQL - 
    /* update
        com.ia.domain.Provider */ update
            provider 
        set
            default_contact_id=?,
            name=?,
            type=?,
            version=?,
            website=? 
        where
            id=? 
            and version=?
Hibernate: 
    /* update
        com.ia.domain.Provider */ update
            provider 
        set
            default_contact_id=?,
            name=?,
            type=?,
            version=?,
            website=? 
        where
            id=? 
            and version=?
2014-07-04 15:06:41,334 [main] [-] TRACE hibernate.type.descriptor.sql.BasicBinder - binding parameter [1] as [BIGINT] - [null]
2014-07-04 15:06:41,334 [main] [-] TRACE hibernate.type.descriptor.sql.BasicBinder - binding parameter [2] as [VARCHAR] - [name_3]
2014-07-04 15:06:41,335 [main] [-] TRACE org.hibernate.type.EnumType - Binding [CARRIER] to parameter: [3]
2014-07-04 15:06:41,336 [main] [-] TRACE hibernate.type.descriptor.sql.BasicBinder - binding parameter [4] as [INTEGER] - [2]
2014-07-04 15:06:41,336 [main] [-] TRACE hibernate.type.descriptor.sql.BasicBinder - binding parameter [5] as [VARCHAR] - [website_3]
2014-07-04 15:06:41,337 [main] [-] TRACE hibernate.type.descriptor.sql.BasicBinder - binding parameter [6] as [BIGINT] - [4]
2014-07-04 15:06:41,338 [main] [-] TRACE hibernate.type.descriptor.sql.BasicBinder - binding parameter [7] as [INTEGER] - [1]
2014-07-04 15:06:41,342 [main] [-] DEBUG org.hibernate.SQL - 
    /* delete one-to-many com.ia.domain.Provider.contracts */ update
            contract 
        set
            provider_id=null 
        where
            provider_id=?
Hibernate: 
    /* delete one-to-many com.ia.domain.Provider.contracts */ update
            contract 
        set
            provider_id=null 
        where
            provider_id=?
2014-07-04 15:06:41,344 [main] [-] TRACE hibernate.type.descriptor.sql.BasicBinder - binding parameter [1] as [BIGINT] - [4]