@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 在数据库中将其 category_policy_id 设置为 null,并插入新的。我想删除原来的那些。
我认为添加 orphanRemoval = true 会做到这一点,但事实并非如此。我在这方面看到的其他问题似乎具有双向关系,将父级设置为 null 可以解决它,但这不是双向关系。
有什么建议吗?
使用 hibernate 3.5.3
编辑: 只有当数据库中存在现有的 AbstractPolicyRule 时才会发生这种情况,我将其从列表中删除,然后再次保存类别。它的外键 category_policy_id 被设置为 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。映射表中的行已删除,但 AbstractPolicyRule 仍包含已删除的项。
最佳答案
我在单向一对多关联中使用 orphanRemoval=true
没有任何问题。
实际上,我测试了您的代码和以下场景(AbstractPolicyRule
正确实现了 equals
/hashCode
):
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());
按预期工作。在生成的痕迹下方:
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。
如果这不能代表您正在做的事情,您也许应该提供更多代码。
更新:回答来自 OP 的评论...
Wow I just changed the saveOrUpdate call to merge and now it's removing appropriately. You have any insight why that is?
只是一个猜测:因为 orphanRemoval
是一个 JPA 东西,我想知道 saveOrUpdate
是否会适本地处理它(实际上,我以为你正在使用 EntityManager
API 因为你提到了 JPA)。
关于java - 即使在一对多关系(JPA/Hibernate)上使用 orphanRemoval=true,孤儿仍保留在数据库中,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3304092/