实体继承和鉴别器列

Question

我正在尝试测试一些 DAO。

我有实体（和表）命名Nomination，它有一些属性：

@Entity(name = "Nomination")
@Table(name = "NOMINATION")
@DiscriminatorColumn(name="CATEGORY_CODE", discriminatorType = DiscriminatorType.STRING, length = 1)

public class Nomination extends AuditableEntity {

@Id
@Column(name = "NOM_ID", insertable = true, updatable = true,
        nullable = false)
@GeneratedValue(strategy = GenerationType.AUTO)
private int id;

@Transient
protected NominationType type = null;

@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST, CascadeType.MERGE})
@JoinColumn(name = "PERIOD_ID", referencedColumnName = "PERIOD_ID")
@Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE,
        org.hibernate.annotations.CascadeType.MERGE})
private NomPeriod period = null;

@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST, CascadeType.MERGE})
@JoinColumn(name = "CATEGORY_CODE", referencedColumnName = "CATEGORY_CODE")
@Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE,
        org.hibernate.annotations.CascadeType.MERGE})
private Category category = null;

@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST, CascadeType.MERGE})
@JoinColumn(name = "NOMINATOR_ID", referencedColumnName = "EMP_ID")
@Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE,
        org.hibernate.annotations.CascadeType.MERGE})
private Employee nominator = null;

@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST, CascadeType.MERGE})
@JoinColumn(name = "STATUS_ID", referencedColumnName = "STATUS_ID")
@Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE,
        org.hibernate.annotations.CascadeType.MERGE})
private Status status = null;

//more after this line

现在我有 4 种不同类型的提名（想法、团队、成功和同事提名）和 4 个不同的表（提名、team_nom、idea_nom、success_nom）。一 (NOMINATION) 具有公共列。这与我称为CoworkerNom. 这个没有单独的表，因为它只需要 NOMINATION 表中列出的内容。其他3个提名是：TeamNom，SuccessNom，和IdeaNom。它们有自己的表，因为它们有额外的数据，因此它们也有自己的实体。例如：

@Entity(name = "IdeaNom")
@Table(name = "IDEA_NOM")
@DiscriminatorValue("I")

public class IdeaNom extends Nomination {

@Column(name = "PURPOSE_INC", insertable = true, updatable = true,
        nullable = true)
private Boolean purposeIncrease;

@Column(name = "PURPOSE_SIMPLIFY", insertable = true, updatable = true,
        nullable = true)
private Boolean purposeSimplify;

//more after this line

此结构适用于SuccessNom和TeamNom。

我在理解如何执行此操作时遇到问题，但现在我已经完成了一些 DAO 并正在尝试对其进行测试。但是我收到以下错误：

Caused by: org.hibernate.MappingException: Repeated column in mapping for entity: 

com.dev.test.data.entity.SuccessNom column: CATEGORY_CODE (should be mapped with insert="false" update="false")
    at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:676)
    at org.hibernate.mapping.PersistentClass.checkPropertyColumnDuplication(PersistentClass.java:698)
    at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:720)
    at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:474)
    at org.hibernate.mapping.SingleTableSubclass.validate(SingleTableSubclass.java:65)
    at org.hibernate.cfg.Configuration.validate(Configuration.java:1362)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1865)
    at org.springframework.orm.hibernate3.LocalSessionFactoryBean.newSessionFactory(LocalSessionFactoryBean.java:860)
    at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:779)
    at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:211)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1479)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1417)
    ... 54 more

首先，CATEGORY_CODE 是鉴别器……但它应该是可写的。希望你们能再次帮助我。

编辑：这是我的架构

Answer 1

如果您需要映射鉴别器列，请使用insert="false" update="false". Hibernate 认为它声明了一次，并且它是不可写的——它只能由 hibernate 管理。此外，加入该专栏有点奇怪。