java – hibernate更新JPA外键

发布时间：2020-12-14 05:27:31 所属栏目：Java 来源：网络整理

导读：新新新新旗新新旗新新旗新新旗新新旗新新旗新新旗新新旗新新旗新新旗 public class TESTClass implements Serializable { ... private String name; @EmbeddedId protected IssTESTPK issTESTPK; @ManyToOne(optional=false) @JoinColumns({ @JoinColumn(nam

新新新新旗新新旗新新旗新新旗新新旗新新旗新新旗新新旗新新旗新新旗

public class TESTClass implements Serializable {

    ...

    private String name;

    @EmbeddedId
    protected IssTESTPK issTESTPK;

    @ManyToOne(optional=false)
    @JoinColumns({
        @JoinColumn(name="DIVISION_CODE",referencedColumnName="DIVISION_CODE",nullable=false,insertable=false,updatable=false),@JoinColumn(name="SURVEY_NUM",referencedColumnName="SURVEY_NUM",updatable=false)})
    private IssDivision issDivision;

}

如果我更改为’name’并调用merge,它可以更新到数据库,但是当我更改issDivision并调用merge时,它不会更新数据库. X- 20045 X- 20045 X- 20045 X- 20045 200：

这是否与我使用embededId(复合主键)相关？

更新

如果我设置upadted = true,我得到以下错误

ERROR - ContextLoader.initWebApplicationContext(215) | Context initialization fa
iled
org.springframework.beans.factory.BeanCreationException: Error creating bean wit
h name 'sessionFactory' defined in ServletContext resource [/WEB-INF/application
Context.xml]: Invocation of init method failed; nested exception is org.hibernat
e.MappingException: Repeated column in mapping for entity: com.compay.test.model
.TESTClass column: SURVEY_NUM (should be mapped with insert="false" update="fa
lse")
        at org.springframework.beans.factory.support.AbstractAutowireCapableBean
Factory.initializeBean(AbstractAutowireCapableBeanFactory.java:1338)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBean
Factory.doCreateBean(AbstractAutowireCapableBeanFactory.java:473)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBean
Factory$1.run(AbstractAutowireCapableBeanFactory.java:409)
        at java.security.AccessController.doPrivileged(Native Method)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBean
Factory.createBean(AbstractAutowireCapableBeanFactory.java:380)
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getOb
ject(AbstractBeanFactory.java:264)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistr
y.getSingleton(DefaultSingletonBeanRegistry.java:222)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBe
an(AbstractBeanFactory.java:261)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean
(AbstractBeanFactory.java:185)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean
(AbstractBeanFactory.java:164)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.
preInstantiateSingletons(DefaultListableBeanFactory.java:423)
        at org.springframework.context.support.AbstractApplicationContext.finish
BeanFactoryInitialization(AbstractApplicationContext.java:728)
        at org.springframework.context.support.AbstractApplicationContext.refres
h(AbstractApplicationContext.java:380)
        at org.springframework.web.context.ContextLoader.createWebApplicationCon
text(ContextLoader.java:255)
        at org.springframework.web.context.ContextLoader.initWebApplicationConte
xt(ContextLoader.java:199)
        at org.springframework.web.context.ContextLoaderListener.contextInitiali
zed(ContextLoaderListener.java:45)
        at org.apache.catalina.core.StandardContext.listenerStart(StandardContex
t.java:3843)
        at org.apache.catalina.core.StandardContext.start(StandardContext.java:4
342)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase
.java:791)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:77
1)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)

        at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.ja
va:627)
        at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.j
ava:553)
        at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:488
)
        at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1149)
        at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java
:311)
        at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(Lifecycl
eSupport.java:117)
        at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)

        at org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
        at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)

        at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443
)
        at org.apache.catalina.core.StandardService.start(StandardService.java:5
16)
        at org.apache.catalina.core.StandardServer.start(StandardServer.java:710
)
        at org.apache.catalina.startup.Catalina.start(Catalina.java:578)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.

解决方法

好吧,我们来看看

你的例外(和着名的)消息是

repeated column in mapping for entity:
column: SURVEY_NUM (should be mapped with insert="false" update="false")

SURVEY_NUM列在哪里？

1oissDivision字段存储一个名为SURVEY_NUM的外键列

@ManyToOne
@JoinColumns({
    @JoinColumn(name="DIVISION_CODE",updatable=false)})
private IssDivision issDivision;

现在,请看下面的映射(请参阅id和accountNumber共享相同的列)

@Entity
public class Account {

    private Integer id;

    private Integer accountNumber;

    @Id
    @Column(name="ACCOUNT_NUMBER")
    public Integer getId() {
        return this.id;
    }

    @Column(name="ACCOUNT_NUMBER")
    public Integer getAccountNumber() {
        return this.accountNumber;
    }

}

现在我们来做如下

Account account = new Account();
account.setId(127359);
account.setAccountNumber(null);

entityManager.persist(account);

Hibernate会问你

Which property should i persist whether both properties shares the same column ??? And as i can see,id property stores a non-null value and accountNumber a null value.

我应该像这样执行一个查询吗？

INSERT INTO ACCOUNT (ACCOUNT_NUMBER,ACCOUNT_NUMBER) VALUES (127359,NULL);

它没有任何意义.因此,这是一个错误的SQL查询;

因为这样,你看到这个好消息

repeated column… blah,blah,blah… (should be mapped with insert=”false” update=”false”)

所以我想你的复合主键称为IssTESTPK也存储一个名为SURVEY_NUM的列.而且您将复合主键属性定义为insert =“false”update =“false”并不是个好主意.避免很多头痛.

请记住：当多个属性共享同一列时,将其中的一个定义为insertable = false,updatable = false.没有其他的.

我认为你的复合主键类应该是这样的

@Embeddable
public class IssTESTPK implements Serializable {

    // Ops... Our missing field which causes our Exception (repeated column... blah,blah...)
    @Column(name="SURVEY_NUM",nullable=false)
    private Integer property;

    private Integer otherProperty;

    private Integer anotherProperty;

    // required no-arg constructor
    public IssTESTPK() {}

    // You must implement equals and hashcode
    public boolean equals(Object o) {
        if(o == null)
            return false;

        if(!(o instanceof IssTESTPK))
            return false;

        IssTESTPK other = (IssTESTPK) o;
        if(!(getProperty().equals(other.getProperty())))
            return false;
        if(!(getOtherProperty().equals(other.getOtherProperty())))
            return false;
        if(!(getAnotherProperty().equals(other.getAnotherProperty())))
            return false;

        return true;
    }

    // NetBeans or Eclipse will worry about it
    public int hashcode() {
        // hashcode code goes here
    }

}

UPDATE

在继续之前

Hibernate does not support automatic generation of compound primary key

保存前必须提供其值.记住它

我们来看看员工复合主键

@Embeddable
public class EmployeeId implements Serializable {

    @Column(name="EMPLOYEE_NUMBER")
    private String employeeNumber;

    @Column(name="SURVEY_NUMBER")
    private BigInteger surveyNumber;

    // getter's and setter's

    // equals and hashcode

}

1o在保存员工之前,您必须提供其值.如上所述,Hibernate不支持复合主键的自动生成

2oHibernate不允许您更新(复合)主键没有意义.

3o其值不能为空

所以,如上所述,我们的EmployeeId可以写成

@Embeddable
public class EmployeeId implements Serializable {

    @Column(name="EMPLOYEE_NUMBER",updatable=false)
    private String employeeNumber;

    @Column(name="SURVEY_NUMBER",updatable=false)
    private BigInteger surveyNumber;

    // getter's and setter's

    // equals and hashcode

}

如上所述

when more than one property shares the same column,define one of them as insertable=false,updatable=false. Nothing else

但是我们不能将复合主键属性标记为insertable = false,updatable = false,因为Hibernate使用它来保存我们的实体

由于Hibernate将使用名为surveyNumber(及其SURVEY_NUMBER列)的复合主键属性来对数据库执行SQL操作,因此我们需要将@ManyToOne除法属性(及其外键列名为SURVEY_NUMBER)重写为可插入= false,可更新= FALSE

// Employee.java

@ManyToOne(fetch=FetchType.LAZY)
@JoinColumns({
    @JoinColumn(name="DIVISION_CODE",referencedColumnName="DIVISION_CODE"),@JoinColumn(name="SURVEY_NUMBER",referencedColumnName="SURVEY_NUMBER",updatable=false)})
private Division division;

4o当您有复合外键时,我们无法混合可插入或不可更新 – 不可更新.

就像是

@ManyToOne(fetch=FetchType.LAZY)
@JoinColumns({
    // I can be updatable
    @JoinColumn(name="DIVISION_CODE",insertable=false),// And i can be insertable
    @JoinColumn(name="SURVEY_NUMBER",updatable=false)})
private Division division;

否则,Hibernate会抱怨

Mixing insertable and non insertable columns in a property is not allowed

因此,名为DIVISION_CODE的复合外键列也应标记为insertable = false,updatable = false以避免上述异常

// Employee.java

@ManyToOne(fetch=FetchType.LAZY)
@JoinColumns({
    @JoinColumn(name="DIVISION_CODE",updatable=false)})
private Division division;

由于我们无法更新DIVISION_CODE列,我们的division属性的行为就像一个常量.那么,您可以想像创建一个名为divisionCode的新属性来改变DIVISION_CODE列,如下所示

// Employee.java

@ManyToOne(fetch=FetchType.LAZY)
@JoinColumns({
    @JoinColumn(name="DIVISION_CODE",updatable=false)})
private Division division;

// Wow,now i expect i can change the value of DIVISION_CODE column
@Column(name="DIVISION_CODE")
private BigInteger divisionCode;

好吧,我们来看看.假设我们有以下DIVISION TABLE

DIVISION TABLE
DIVISION_CODE     SURVEY_NUMBER
1                 10
2                 11
3                 12
4                 13
5                 14

记住：Division和Employee之间有一个外键约束

你想到了

I can not change division property because of insertable=false,updatable=false. But i can change divisionCode property (and its DIVISION_CODE column) as a way to change the foreign key column called DIVISION_CODE

您执行以下代码

employee.setDivisionCode(7);

哇,见上面的DIVISION_TABLE. DIVISION_CODE列中的某些值是否等于7？

答案很清楚：否(你会看到约束违规)

所以,这是一个不一致的映射. Hibernate不允许.

问候,

（编辑：李大同）

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