嵌入式ID和“实体映射中的重复列..."例外 [英] Embedded id and "repeated column in mapping for entity..." exception

问题描述

我在使用JPA和Hibernate时遇到问题，但无法解决.

I have a problem with JPA and Hibernate and I fail to solve it.

所以，这是我的applicationContext.xml:

So, it is my applicationContext.xml:

<context:component-scan base-package="com.abt.fiifootballmanager">
    <context:exclude-filter type="annotation"
        expression="org.springframework.stereotype.Controller" />
</context:component-scan>

<jdbc:embedded-database type="HSQL" id="dataSource" />

<bean
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
    id="emf">
    <property name="packagesToScan" value="com.abt.fiifootballmanager.entity" />
    <property name="dataSource" ref="dataSource" />
    <property name="jpaProperties">
        <props>
            <prop key="hibernate.show_sql">true</prop>
            <prop key="hibernate.hbm2ddl.auto">create</prop>
        </props>
    </property>
    <property name="persistenceProvider">
        <bean class="org.hibernate.jpa.HibernatePersistenceProvider" />
    </property>
</bean>

<tx:annotation-driven transaction-manager="transactionManager"/>

<bean class="org.springframework.orm.jpa.JpaTransactionManager" id="transactionManager">
    <property name="dataSource" value="dataSource"/>
</bean>

这是我的表演实体:

 package com.abt.fiifootballmanager.entity;

import java.io.Serializable;
import javax.persistence.*;
import java.math.BigDecimal;
import java.util.List;

@Entity
@Table(name="PERFORMANCES")
@NamedQuery(name="Performance.findAll", query="SELECT p FROM Performance p")
public class Performance implements Serializable {
    private static final long serialVersionUID = 1L;

    @EmbeddedId
    private PerformancePK id;

    @Column(name="RED_CARD")
    private BigDecimal redCard;

    @Column(name="YELLOW_CARD")
    private BigDecimal yellowCard;

    @OneToOne(mappedBy="performance")
    private GoalkeepingPerformance goalkeepingPerformance;

    @OneToMany(mappedBy="performance")
    private List<OutfieldPerformance> outfieldPerformances;

    @ManyToOne
    @JoinColumn(name="MATCH_ID")
    private Match match;

    @ManyToOne
    @JoinColumn(name="PLAYER_ID")
    private Player player;
    ...getters & setters }

这是我的嵌入式id类:

And this is my embedded id class:

@Embeddable
public class PerformancePK implements Serializable {
    //default serial version id, required for serializable classes.
    private static final long serialVersionUID = 1L;

    @Column(name="MATCH_ID", insertable=false, updatable=false)
    private long matchId;

    @Column(name="PLAYER_ID", insertable=false, updatable=false)
    private long playerId;
    ... //getters and setters

所以，这些是我的课程.但是，当我想运行我的应用程序时，会遇到下一个异常: 1.Error creating bean with name 'emf' defined in ServletContext resource [/WEB-INF/applicationContext.xml]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory

So, these are my classes. But when I want to run my application I get the next exceptions: 1.Error creating bean with name 'emf' defined in ServletContext resource [/WEB-INF/applicationContext.xml]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory

2. Repeated column in mapping for entity: com.abt.fiifootballmanager.entity.Performance column: MATCH_ID (should be mapped with insert="false" update="false")

我认为第一个异常是由第二个异常引起的.那么，为什么我会得到实体映射中的重复列?".使用嵌入式id类是个好主意吗?.

I think that the first exception it's caused by the second. So, why I get "Repeated column in mapping for entity?". It's a good idea to use an embedded id class?.

推荐答案

您的Performance类中的两个变量match和player映射到与嵌入式中matchId和playerId相同的列ID.如错误所述，它们应与insert ="false" update ="false"映射.

Your two variables match and player in your Performance class are mapped to the same columns as matchId and playerId in the embedded ID. As the error says, they "should be mapped with insert="false" update="false"".

@ManyToOne
@JoinColumn(name="MATCH_ID", insertable = false, updatable = false)
private Match match;

@ManyToOne
@JoinColumn(name="PLAYER_ID", insertable = false, updatable = false)
private Player player;

这实际上使这些字段为只读，因此，如果更改了嵌入式ID中的值，则Hibernate仅知道更改MATCH_ID和PLAYER_ID列，而如果更改​​了match或player的值，则不会更改

This essentially makes those fields readonly, so Hibernate knows only to change the MATCH_ID and PLAYER_ID columns if the values in the embedded ID are changed, but not if the values of match or player are changed.

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