7

这是我的 JPA 实体类:

@Cacheable
@Entity
public class JpaItemSearchRequest implements ItemSearchRequest {

    @Id
    @GeneratedValue
    private long id;

    @Enumerated(EnumType.STRING)
    private SearchIndex searchIndex;

    private String browseNode;
    private String keywords;

    @Enumerated(EnumType.STRING)
    @ElementCollection
    private Set<ResponseGroup> responseGroups = new HashSet<ResponseGroup>();

    private int itemPage;

    @Enumerated(EnumType.STRING)
    private Locale locale;

    ... end of fields ...
}

SearchIndex, ResponseGroup, 和Locale是枚举。

这个类有一个相当复杂的唯一约束:一个组合 (searchIndex, browseNode, keywords, responseGroups, itemPage, locale)被认为是唯一的。

所以我在类中添加了以下约束注释:

@Table(uniqueConstraints = { @UniqueConstraint(columnNames = { "searchIndex", "browseNode", "keywords", "responseGroups", "itemPage", "locale" }) })

当我尝试锻炼我的课程时,出现以下异常:

 org.hibernate.AnnotationException: Unable to create unique key constraint (searchIndex, browseNode, keywords, responseGroups, itemPage, locale) on table JpaItemSearchRequest: database column responseGroups not found. Make sure that you use the correct column name which depends on the naming strategy in use (it may not be the same as the property name in the entity, especially for relational types)
    at org.hibernate.cfg.Configuration.buildUniqueKeyFromColumnNames(Configuration.java:1584) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final]
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1386) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final]
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1737) ~[hibernate-core-4.1.7.Final.jar:4.1.7.Final]
    at org.hibernate.ejb.EntityManagerFactoryImpl.<init>(EntityManagerFactoryImpl.java:94) ~[hibernate-entitymanager-4.1.7.Final.jar:4.1.7.Final]
    at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:905) ~[hibernate-entitymanager-4.1.7.Final.jar:4.1.7.Final]
    ... 74 common frames omitted

(我使用Hibernate 4.1.7.Final作为 JPA 实现/服务提供者)

例外要点是:database column responseGroups not found.

如果我没有在幕后为我的单个实体类指定该约束,Hibernate 会生成两个表:一个用于所有“简单”实体数据,另一个用于Set<ResponseGroup> responseGroups实体数据:

CREATE TABLE `jpaitemsearchrequest` (
    `id` BIGINT(20) NOT NULL AUTO_INCREMENT,
    `browseNode` VARCHAR(255) NULL DEFAULT NULL,
    `itemPage` INT(11) NOT NULL,
    `keywords` VARCHAR(255) NULL DEFAULT NULL,
    `locale` VARCHAR(255) NULL DEFAULT NULL,
    `searchIndex` VARCHAR(255) NULL DEFAULT NULL,
    PRIMARY KEY (`id`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB
AUTO_INCREMENT=3;

...

CREATE TABLE `jpaitemsearchrequest_responsegroups` (
    `JpaItemSearchRequest_id` BIGINT(20) NOT NULL,
    `responseGroups` VARCHAR(255) NULL DEFAULT NULL,
    INDEX `FKC217757B99AE0422` (`JpaItemSearchRequest_id`),
    CONSTRAINT `FKC217757B99AE0422` FOREIGN KEY (`JpaItemSearchRequest_id`) REFERENCES `jpaitemsearchrequest` (`id`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB;

如何正确表达我的约束?


编辑

这个问题曾经阅读过:
JPA: Unique constraint across a Set (...unique constraint on another table)

进一步思考我的问题,我确信它可以归结为以下问题:
JPA:如何表达一个包含@ElementCollection 列的唯一约束?

4

1 回答 1

12

可以通过将@CollectionTable与元素集合一起使用来定义集合表中列的唯一约束。

@CollectionTable(
    uniqueConstraints= @UniqueConstraint(columnNames={"col1","col2"})
)

如前所述,这些是映射元素集合的表格列。无法对多个表中的列进行唯一约束。

于 2013-02-13T22:05:04.783 回答