即使在一对多关系中使用orphanRemoval = true,孤儿仍保留在数据库中(JPA/Hibernate)

Question

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@Table(name = "company_policies")
@DiscriminatorColumn(name = "rule_name")
public abstract class AbstractPolicyRule implements Serializable {

  @Transient
  private static final long serialVersionUID = 1L;

  @Id
  @GeneratedValue
  private Long id;
  private String value;

  ...
}

_

@Entity
public class Category implements Serializable {

  @Transient
  private static final long serialVersionUID = 1L;

  @Id
  @GeneratedValue
  private Long id;
  @Column(name = "category_name")
  private String name;

  @OneToMany(fetch = FetchType.EAGER, cascade = { CascadeType.ALL }, orphanRemoval = true)
  @JoinColumn(name = "category_policy_id", referencedColumnName = "id")
  private Set<AbstractPolicyRule> activePolicyRules;

  ...
}

更新此Set时,现有的activePolicyRules将其category_policy_id在数据库中设置为null,并插入新的.我希望删除原来的.

我认为添加orphanRemoval = true会这样做,但事实并非如此.我在其上看到的其他问题似乎具有双向关系,并且将父设置为null可以解决它,但这不是双向关系.

有什么建议？

使用Hibernate 3.5.3

编辑:这只发生在数据库中存在现有的AbstractPolicyRule时,我将其从列表中删除,然后再次保存类别.它的外键category_policy_id设置为null而不是被删除.

[DEBUG] Collection found: [domain.category.Category.activePolicyRules#1], was: 
[<unreferenced>] (initialized)
[DEBUG] Flushed: 0 insertions, 2 updates, 0 deletions to 2 objects
[DEBUG] Flushed: 1 (re)creations, 0 updates, 1 removals to 1 collections
...
[DEBUG] Deleting collection: [domain.category.Category2.activePolicyRules#1]
[DEBUG] about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
[DEBUG] update company_policies set category_policy_id=null where category_policy_id=?
[DEBUG] done deleting collection

还尝试了一个连接表,因为Hibernate文档不鼓励以前的方式:

@Entity
public class Category implements Serializable {

  @Transient
  private static final long serialVersionUID = 1L;

  @Id
  @GeneratedValue
  private Long id;
  @Column(name = "category_name")
  private String name;

  @OneToMany(fetch = FetchType.EAGER, cascade = { CascadeType.ALL }, orphanRemoval = true)
  @JoinTable(name = "policy_rule_mapping", 
    joinColumns = @JoinColumn(name = "category_id"), 
    inverseJoinColumns = @JoinColumn(name = "rule_id"))
  private Set<AbstractPolicyRule> activePolicyRules;

  ...
}

这有同样的问题.删除映射表中的行,但AbstractPolicyRule仍包含已删除的项.

Answer 1

我正在使用orphanRemoval=true单向一对多关联而没有任何问题.

实际上,我测试了您的代码和以下场景(AbstractPolicyRule实现equals/ hashCode正确):

Category category = new Category();
AbstractPolicyRule policyRule1 = new AbstractPolicyRule("foo");

category.addToActivePolicyRules(policyRule1);
em.persist(category);
em.flush();

assertNotNull(category.getId());
assertNotNull(category.getActivePolicyRules());
assertEquals(1, category.getActivePolicyRules().size());

category.removeFromActivePolicyRules(policyRule1);
category.addToActivePolicyRules(new AbstractPolicyRule("bar"));
// category = em.merge(category); // works with or without
em.flush();
assertEquals(1, category.getActivePolicyRules().size());

只是按预期工作.下面生成的跟踪:

22:54:30.817 [main] DEBUG org.hibernate.SQL - insert into Category (id, category_name) values (null, ?)
Hibernate: insert into Category (id, category_name) values (null, ?)
22:54:30.824 [main] TRACE org.hibernate.type.StringType - binding null to parameter: 1
22:54:30.844 [main] DEBUG o.h.id.IdentifierGeneratorHelper - Natively generated identity: 1
...
22:54:30.872 [main] DEBUG org.hibernate.SQL - insert into AbstractPolicyRule (id, name) values (null, ?)
Hibernate: insert into AbstractPolicyRule (id, name) values (null, ?)
22:54:30.873 [main] TRACE org.hibernate.type.StringType - binding 'foo' to parameter: 1
22:54:30.874 [main] DEBUG o.h.id.IdentifierGeneratorHelper - Natively generated identity: 1
...
22:54:30.924 [main] DEBUG org.hibernate.SQL - update AbstractPolicyRule set category_policy_id=? where id=?
Hibernate: update AbstractPolicyRule set category_policy_id=? where id=?
22:54:30.927 [main] TRACE org.hibernate.type.LongType - binding '1' to parameter: 1
22:54:30.928 [main] TRACE org.hibernate.type.LongType - binding '1' to parameter: 2
22:54:30.929 [main] DEBUG o.h.p.c.AbstractCollectionPersister - done inserting collection: 1 rows inserted
22:54:30.929 [main] DEBUG org.hibernate.jdbc.AbstractBatcher - Executing batch size: 1
...
22:54:30.945 [main] DEBUG org.hibernate.SQL - insert into AbstractPolicyRule (id, name) values (null, ?)
Hibernate: insert into AbstractPolicyRule (id, name) values (null, ?)
22:54:30.948 [main] TRACE org.hibernate.type.StringType - binding 'bar' to parameter: 1
22:54:30.948 [main] DEBUG o.h.id.IdentifierGeneratorHelper - Natively generated identity: 2
...
22:54:30.990 [main] DEBUG org.hibernate.SQL - update AbstractPolicyRule set category_policy_id=null where category_policy_id=? and id=?
Hibernate: update AbstractPolicyRule set category_policy_id=null where category_policy_id=? and id=?
22:54:30.991 [main] TRACE org.hibernate.type.LongType - binding '1' to parameter: 1
22:54:30.992 [main] TRACE org.hibernate.type.LongType - binding '1' to parameter: 2
22:54:30.993 [main] DEBUG o.h.p.c.AbstractCollectionPersister - done deleting collection rows: 1 deleted
22:54:30.993 [main] DEBUG o.h.p.c.AbstractCollectionPersister - Inserting rows of collection: [com.stackoverflow.q3304092.Category.activePolicyRules#1]
22:54:30.994 [main] DEBUG org.hibernate.jdbc.AbstractBatcher - Executing batch size: 1
...
22:54:30.996 [main] DEBUG org.hibernate.SQL - update AbstractPolicyRule set category_policy_id=? where id=?
Hibernate: update AbstractPolicyRule set category_policy_id=? where id=?
22:54:30.997 [main] TRACE org.hibernate.type.LongType - binding '1' to parameter: 1
22:54:30.998 [main] TRACE org.hibernate.type.LongType - binding '2' to parameter: 2
22:54:31.002 [main] DEBUG o.h.p.c.AbstractCollectionPersister - done inserting rows: 1 inserted
...
22:54:31.015 [main] DEBUG org.hibernate.SQL - delete from AbstractPolicyRule where id=?
Hibernate: delete from AbstractPolicyRule where id=?
22:54:31.017 [main] TRACE org.hibernate.type.LongType - binding '1' to parameter: 1

第一个策略规则被删除.

如果这不代表您正在做的事情,您应该提供更多代码.

更新:回答OP的评论......

哇,我刚刚将saveOrUpdate调用更改为merge,现在正在适当删除.你有什么见解为什么会这样？

只是一个猜测:既然orphanRemoval是一个JPA的东西,我想知道是否saveOrUpdate会适当地处理它(实际上,我认为你使用EntityManagerAPI,因为你提到了JPA).