java - hibernate 更新JPA外键

Question

我的 jpa 如下所示

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", nullable=false, insertable=false, updatable=false)})
    private IssDivision issDivision;

}

如果我更改“名称”并调用合并，它能够更新到数据库中，但是当我更改 issDivision 并调用合并时，它不会更新数据库。如何解决这个问题？

这与我使用的是 embededId(复合主键)有关吗？

已更新

如果我设置 upadted=true，我会得到以下错误

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.

Answer 1

好吧，让我们看看

您的异常(和著名)消息是

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

SURVEY_NUM 列位于何处？

1º issDivision 字段存储一个名为 SURVEY_NUM 的外键列

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

现在，查看以下映射(查看 id 和 accountNumber 共享同一列)

@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;
    }

}

现在让我们做如下

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.

我应该执行这样的查询吗？？？

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

没有意义。因此，这是一个错误的SQL查询；

正因为如此，你看到了这个好消息

repeated column... blah, blah, blah... (should be mapped with insert="false" update="false")

所以我想您名为 IssTESTPK 的复合主键还存储名为 SURVEY_NUM 的列。 这不是一个好主意，您将复合主键属性定义为 insert="false"update="false"。避免很多头痛。

请记住:当多个属性共享同一列时，将其中之一定义为 insertable=false、updatable=false。 没有别的。

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, 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
    }

}

---

更新

---

继续之前

Hibernate does not support automatic generation of compound primary key

您必须在保存前提供它的值。记在心里

让我们看看员工复合主键

@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 Employee 之前，您必须提供它的值。上面说了，Hibernate不支持自动生成复合主键

2º Hibernate 不允许您更新(复合)主键这没有意义。

3º 其值不能为空

所以，根据上面的描述，我们的EmployeeId可以写成

@Embeddable
public class EmployeeId implements Serializable {

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

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

    // getter's and setter's

    // equals and hashcode

}

如前所述

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 的复合主键属性(及其 SURVEY_NUMBER 列)对数据库执行 SQL 操作，因此我们需要重写我们的 @ManyToOne 分部属性(及其名为 SURVEY_NUMBER 的外键列)为 insertable=假的，可更新的=假的

// Employee.java

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

4º 当您有复合外键时，我们不能混合可插入-不可插入或可更新-不可更新。

有点像

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

否则，Hibernate 会报错

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

正因为如此，它的名为 DIVISION_CODE 的复合外键列也应该标记为 insertable=false, updatable=false 以避免上面显示的异常

// Employee.java

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

由于我们无法再更新 DIVISION_CODE 列，我们的除法属性表现得像常量。然后，您考虑创建一个名为 divisionCode 的新属性来更改 DIVISION_CODE 列，如下所示

// Employee.java

@ManyToOne(fetch=FetchType.LAZY)
@JoinColumns({
    @JoinColumn(name="DIVISION_CODE", referencedColumnName="DIVISION_CODE", insertable=false, updatable=false),
    @JoinColumn(name="SURVEY_NUMBER", referencedColumnName="SURVEY_NUMBER", insertable=false, 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，让我们看看。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

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

员工.setDivisionCode(7);

哇哦，请参阅上面的 DIVISION_TABLE。 DIVISION_CODE 列中是否有某个值等于 7？

答案很明确:否(您会看到违反约束)

所以，这是一个不一致的映射。 Hibernate 不允许这样做。

问候，