无法添加或更新子行：外键约束失败（`mypractice`.`customer`，CONSTRAINT`FKqoqd` FOREIGN KEY（`forevenid`）

Question

在休眠状态下进行一对多映射的示例时，我遇到了一个错误：

ERROR: Cannot add or update a child row: a foreign key constraint fails (`mypractice`.`customer`, CONSTRAINT `FKqoqsbb1kdy5makybbues6t42d` FOREIGN KEY (`forevenid`) REFERENCES `vendor` (`vid`))
Mar 21, 2019 10:07:44 AM org.hibernate.engine.jdbc.batch.internal.AbstractBatchImpl release
INFO: HHH000010: On release of batch it still contained JDBC statements
Mar 21, 2019 10:07:44 AM org.hibernate.internal.ExceptionMapperStandardImpl mapManagedFlushFailure
ERROR: HHH000346: Error during managed flush [org.hibernate.exception.ConstraintViolationException: could not execute statement]
Exception in thread "main" javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException: could not execute statement
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:147)
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:155)
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:162)
    at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1402)
    at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:472)
    at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3132)
    at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2369)
    at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:467)
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:147)
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$100(JdbcResourceLocalTransactionCoordinatorImpl.java:38)
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:221)
    at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:68)
    at com.onetomany.OurLogic.main(OurLogic.java:52)
Caused by: org.hibernate.exception.ConstraintViolationException: could not execute statement
    at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:59)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:97)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:207)
    at org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:45)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2934)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3434)
    at org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:89)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:560)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:434)
    at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:337)
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39)
    at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1396)
    ... 9 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`mypractice`.`customer`, CONSTRAINT `FKqoqsbb1kdy5makybbues6t42d` FOREIGN KEY (`forevenid`) REFERENCES `vendor` (`vid`))
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.base/java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
    at com.mysql.jdbc.Util.getInstance(Util.java:387)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:932)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3878)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3814)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2478)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2625)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2551)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
    at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2073)
    at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2009)
    at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5094)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1994)
    at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:204)
    ... 18 more

Vendor.java

package com.onetomany;

import java.util.Set;

public class Vendor {

    private int vendorId;
    private String vendorName;
    private Set children;

    public int getVendorId() {
        return vendorId;
    }

    public void setVendorId(int vendorId) {
        this.vendorId = vendorId;
    }

    public String getVendorName() {
        return vendorName;
    }

    public void setVendorName(String vendorName) {
        this.vendorName = vendorName;
    }

    public Set getChildren() {
        return children;
    }

    public void setChildren(Set children) {
        this.children = children;
    }

}

Customer.java

package com.onetomany;

public class Customer {

    private int customerId;
    private String customerName;
    private int forevenId;

    public int getCustomerId() {
        return customerId;
    }

    public void setCustomerId(int customerId) {
        this.customerId = customerId;
    }

    public String getCustomerName() {
        return customerName;
    }

    public void setCustomerName(String customerName) {
        this.customerName = customerName;
    }

    public int getForevenId() {
        return forevenId;
    }

    public void setForevenId(int forevenId) {
        this.forevenId = forevenId;
    }

}

Customer.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.onetomany">
<class name ="Customer" table = "customer">
<id name = "customerId" column = "cid"/>
<property name = "customerName" column ="cname"/>

<property name = "forevenId" column="forevenid"/>

</class>
</hibernate-mapping>

Vendor.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.onetomany">
<class name="Vendor" table="vendor">

<id name= "vendorId" column ="vid"/>
<property name="vendorName" column="vname"/>

<set name="children" cascade="all">

<key column="forevenid"/>
<one-to-many class="Customer"/>

</set>
</class>
</hibernate-mapping>

hibernate.cfg.xml

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>

<!-- creating jdbc connect -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/mypractice?useSSL=false</property>
<property name="connection.user">root</property>
<property name="connection.password">root</property>


<!-- hibernate specific information -->

<property name="show_sql">true</property>
<property name="hbm2ddl.auto">update</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>

<!-- mapping file -->
<mapping resource="Product.hbm.xml"/>

</session-factory>
</hibernate-configuration>

OurLogic.java

package com.onetomany;

import java.util.HashSet;
import java.util.Set;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

public class OurLogic {

    public static void main(String[] args) {

        Configuration cfg = new Configuration();
        cfg.configure("hibernate.cfg.xml");

        SessionFactory factory = cfg.buildSessionFactory();
        Session session = factory.openSession();

        //PARENT OBJECT
        Vendor v= new Vendor();

        v.setVendorId(101);
        v.setVendorName("Lenovo");

        //3 child obj

        Customer c1= new Customer();
        c1.setCustomerId(504);
        c1.setCustomerName("xyz");


        Customer c2 = new Customer();
        c2.setCustomerId(505);
        c2.setCustomerName("abc");

        Customer c3  = new Customer();
        c3.setCustomerId(506);
        c3.setCustomerName("uvx");

        //adding child obj to set , as we taken 3 property data in parent 
        Set s =  new HashSet();
        s.add(c1);
        s.add(c2);
        s.add(c3);
        v.setChildren(s);

        Transaction tx =  session.beginTransaction();
        session.save(v);

        tx.commit();
        session.close();
        System.out.println("one to many is done");
        factory.close();



    }

}