Question

我在jpa中使用单继承将数据插入表时面临以下问题。

    run:
[EL Info]: 2014-04-17 22:40:45.947--ServerSession(863001717)--EclipseLink, version: Eclipse Persistence Services - 2.2.0.v20110202-r8913
[EL Info]: 2014-04-17 22:40:46.387--ServerSession(863001717)--file:/C:/Users/xone/Documents/NetBeansProjects/JPAAditiDAS/build/classes/_TESTJPAPU login successful
[EL Warning]: 2014-04-17 22:40:46.469--ClientSession(1037426453)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.2.0.v20110202-r8913): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'customerjpa.sequence' doesn't exist
Error Code: 1146
Call: UPDATE SEQUENCE SET SEQ_COUNT = SEQ_COUNT + ? WHERE SEQ_NAME = ?
    bind => [2 parameters bound]
Query: DataModifyQuery(name="SEQUENCE" sql="UPDATE SEQUENCE SET SEQ_COUNT = SEQ_COUNT + ? WHERE SEQ_NAME = ?")
Exception in thread "main" Local Exception Stack: 
Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.2.0.v20110202-r8913): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'customerjpa.sequence' doesn't exist
Error Code: 1146
Call: UPDATE SEQUENCE SET SEQ_COUNT = SEQ_COUNT + ? WHERE SEQ_NAME = ?
    bind => [2 parameters bound]
Query: DataModifyQuery(name="SEQUENCE" sql="UPDATE SEQUENCE SET SEQ_COUNT = SEQ_COUNT + ? WHERE SEQ_NAME = ?")
    at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:324)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:798)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeNoSelect(DatabaseAccessor.java:864)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.basicExecuteCall(DatabaseAccessor.java:583)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeCall(DatabaseAccessor.java:526)
    at org.eclipse.persistence.internal.sessions.AbstractSession.basicExecuteCall(AbstractSession.java:1729)
    at org.eclipse.persistence.sessions.server.ClientSession.executeCall(ClientSession.java:234)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:207)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:193)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeNoSelectCall(DatasourceCallQueryMechanism.java:236)
    at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeNoSelect(DatasourceCallQueryMechanism.java:216)
    at org.eclipse.persistence.queries.DataModifyQuery.executeDatabaseQuery(DataModifyQuery.java:85)
    at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:808)
    at org.eclipse.persistence.internal.sessions.AbstractSession.internalExecuteQuery(AbstractSession.java:2800)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1521)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1503)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1477)
    at org.eclipse.persistence.sequencing.QuerySequence.update(QuerySequence.java:336)
    at org.eclipse.persistence.sequencing.QuerySequence.updateAndSelectSequence(QuerySequence.java:275)
    at org.eclipse.persistence.sequencing.StandardSequence.getGeneratedVector(StandardSequence.java:71)
    at org.eclipse.persistence.sequencing.DefaultSequence.getGeneratedVector(DefaultSequence.java:163)
    at org.eclipse.persistence.sequencing.Sequence.getGeneratedVector(Sequence.java:257)
    at org.eclipse.persistence.internal.sequencing.SequencingManager$Preallocation_Transaction_NoAccessor_State.getNextValue(SequencingManager.java:474)
    at org.eclipse.persistence.internal.sequencing.SequencingManager.getNextValue(SequencingManager.java:961)
    at org.eclipse.persistence.internal.sequencing.ClientSessionSequencing.getNextValue(ClientSessionSequencing.java:70)
    at org.eclipse.persistence.internal.descriptors.ObjectBuilder.assignSequenceNumber(ObjectBuilder.java:292)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.assignSequenceNumber(UnitOfWorkImpl.java:454)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.registerNotRegisteredNewObjectForPersist(UnitOfWorkImpl.java:4190)
    at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.registerNotRegisteredNewObjectForPersist(RepeatableWriteUnitOfWork.java:493)
    at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.registerNewObjectForPersist(UnitOfWorkImpl.java:4135)
    at org.eclipse.persistence.internal.jpa.EntityManagerImpl.persist(EntityManagerImpl.java:406)
    at test.SingleInheritenceCustTest.main(SingleInheritenceCustTest.java:35)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'customerjpa.sequence' doesn't exist
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.Util.getInstance(Util.java:386)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1053)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4120)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4052)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2503)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2664)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2794)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2458)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2375)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2359)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:789)
    ... 30 more
Java Result: 1
BUILD SUCCESSFUL (total time: 2 seconds)

主类：

package test;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
import javax.persistence.Query;

import entity.CustomerSingle;
import entity.OnlineCustomer;

/*
 * This is a test class for testing Single table inheritance
 */
public class SingleInheritenceCustTest {

    public static void main(String[] args) {
        EntityManagerFactory entityManagerFactory =  Persistence.createEntityManagerFactory("TESTJPAPU");

        EntityManager em = entityManagerFactory.createEntityManager();
        EntityTransaction userTransaction = em.getTransaction();

    userTransaction.begin();
    //inserting Customer
    CustomerSingle customer = new CustomerSingle();
    customer.setFirstName("Antony");
    customer.setLastName("John");
    customer.setCustType("RETAIL");
    customer.getAddress().setStreet("1 Broad street");
    customer.getAddress().setAppt("111");
    customer.getAddress().setCity("NewYork");
    customer.getAddress().setZipCode("23456");
    em.persist(customer);
    inserting Online Customer
    OnlineCustomer onlineCust = new OnlineCustomer();
    onlineCust.setFirstName("Henry");
    onlineCust.setLastName("Ho");
    onlineCust.setCustType("ONLINE");
    onlineCust.getAddress().setStreet("1 Mission Street");
    onlineCust.getAddress().setAppt("222");
    onlineCust.getAddress().setCity("Seatle");
    onlineCust.getAddress().setZipCode("33345");
    onlineCust.setWebsite("www.amazon.com");
    em.persist(onlineCust);
    userTransaction.commit();

    // fetch only the online customers
    /*Query query = em.createQuery("SELECT customer FROM ONLINECUSTOMER customer");
    List<OnlineCustomer> list= query.getResultList();
    System.out.println("The list is: "+ list);
    for(int i=0;i<list.size();i++){
        System.out.println("ONLINE CUSTOMER ["+ i +"] " +  list.get(i));
    }*/
    em.close();
    entityManagerFactory.close();


}

}

实体类CustomerSingle：它包含客户的共同特征。它用于通过使用歧视值＆＃34;零售＆＃34;

来插入数据

package entity;
import javax.persistence.*;

import java.io.Serializable;
import java.util.Date;
/*
 * CUSTOMER ENTITY CLASS -> This is an example of Single table inheritance
 */
    @Table(name="CUSTOMER")
    @Entity(name = "CUSTOMER2") //Name of the entity
    @Inheritance(strategy=InheritanceType.SINGLE_TABLE)
    @DiscriminatorColumn(name="CUST_TYPE", discriminatorType=DiscriminatorType.STRING,length=10)
    @DiscriminatorValue("RETAIL")

public class CustomerSingle implements Serializable{
    @Id //signifies the primary key
    @Column(name = "CUST_ID", nullable = false)
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long custId;

    @Column(name = "FIRST_NAME", nullable = false,length = 50)
    private String firstName;

    @Column(name = "LAST_NAME", length = 50)
    private String lastName;

    @Embedded
    private Address address = new Address();

    @Column(name = "CUST_TYPE", length = 10)
    private String custType;

    @Column(name = "LAST_UPDATED_TIME")
             @Temporal(TemporalType.TIMESTAMP)
    private Date updatedTime;

    public long getCustId() {
        return custId;
    }

    public void setCustId(long custId) {
        this.custId = custId;
    }


    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public Date getUpdatedTime() {
        return updatedTime;
    }

    public void setUpdatedTime(Date updatedTime) {
        this.updatedTime = updatedTime;
    }
    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public String getCustType() {
        return custType;
    }



public void setCustType(String custType) {
            this.custType = custType;
        }

//      

     ToString()
            public String toString() {
               StringBuffer sb = new StringBuffer();
               sb.append("custId : " + custId);
               sb.append("   First Name : " + firstName);
               sb.append("   Last Name : " + lastName);
               sb.append("   customer type : " + custType);

               return sb.toString();
            }

}

ONLINECUSTOMER是另一个扩展CUSTOMERSINGLE的实体类。它用于通过使用歧视值插入数据＆＃34; ONLINE＆＃34;

package entity;
import javax.persistence.*;


/*
 * ONLINE CUSTOMER ENTITY CLASS -> This is an example of Single table inheritance
 */

@Entity(name = "ONLINECUSTOMER") //Name of the entity
@DiscriminatorValue("ONLINE")

public class OnlineCustomer extends CustomerSingle{
    @Column(name = "WEBSITE", length = 100)
    private String website;

    public String getWebsite() {
        return website;
    }

    public void setWebsite(String website) {
        this.website = website;
    }

    public String toString() {
         StringBuffer sb = new StringBuffer();
         sb.append(super.toString());
         sb.append(" website: "+website);
         return sb.toString();
    }

}

Answer 1

异常是由于底层数据库中缺少序列表引起的：

Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: 
Table 'customerjpa.sequence' doesn't exist

根据配置，有两种解决方案：

让EclipseLink通过在pesistence.xml中指定eclipselink.ddl-generation来为您完成。（优选的）
通过执行SQL语句创建序列manually。

表'customerjpa.sequence'不存在JPA

1 个答案: