即使将hibernate.hbm2ddl.auto设置为create，Hibernate也无法删除模式

Question

下面是我定义的hibernate.cfg.xml

    <session-factory>

    <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="connection.driver_class">com.mysql.jdbc.Driver
    </property>
    <property     name="connection.url">
    jdbc:mysql://127.0.0.1:3307/pankaj</property>
    <property name="connection.username">root</property>
    <property name="connection.password">hello</property>

    <property name="connection.pool_size">1</property>
    <property    name="dialect">org.hibernate.dialect.MySQLDialect
    </property>
    <property name="current_session_context_class">thread</property>
    <property name="cache.provider_class">
    org.hibernate.cache.NoCacheProvider</property>
    <property name="show_sql">true</property>
    <property name="hibernate.hbm2ddl.auto">create</property>


       <mapping class ="com.Panky.UserDetails" /> 
        <!-- <mapping class ="com.panky.Vehicle" /> -->
  </session-factory>

</hibernate-configuration>

下面是测试hibernate的测试类

package com.Panky;

import java.util.Date;

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

public class HibernateTest {

        public static void main(String[] args) {

        System.out.println("hello");
        UserDetails user=new UserDetails();
        user.setId(1);
        user.setUsername("Pankaj");

        UserDetails user1=new UserDetails();
        user1.setId(2);
        user1.setUsername("Pankaj");

        SessionFactory sessionFactory
        = new Configuration().configure().buildSessionFactory();                  
        Session session=sessionFactory.openSession();
        session.beginTransaction();
        session.save(user);
        session.save(user1);
        session.getTransaction().commit();
        session.close();
        sessionFactory.close();
        }

       }

UserDetails.java

 import javax.persistence.Entity;
 import javax.persistence.Id;
 import javax.persistence.Table;



    @Entity
    @Table(name ="User_details")
    public class UserDetails {
    @Id
    @Column(name="ID")
    private int id;
    @Column(name="User_Name")
    private String username;

    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }




    }

控制台输出：

    Jul 23, 2016 5:08:11 PM org.hibernate.annotations.common.Version
    <clinit>
    INFO: HCANN000001: Hibernate Commons Annotations {4.0.1.Final}
    Jul 23, 2016 5:08:11 PM org.hibernate.Version logVersion
    INFO: HHH000412: Hibernate Core {4.0.0.Final}
    Jul 23, 2016 5:08:11 PM org.hibernate.cfg.Environment <clinit>
    INFO: HHH000206: hibernate.properties not found
    Jul 23, 2016 5:08:11 PM org.hibernate.cfg.Environment 
    buildBytecodeProvider
    INFO: HHH000021: Bytecode provider name : javassist
    Jul 23, 2016 5:08:11 PM org.hibernate.cfg.Configuration configure
    INFO: HHH000043: Configuring from resource: /hibernate.cfg.xml
    Jul 23, 2016 5:08:11 PM org.hibernate.cfg.Configuration 
    getConfigurationInputStream
    INFO: HHH000040: Configuration resource: /hibernate.cfg.xml
    Jul 23, 2016 5:08:11 PM org.hibernate.cfg.Configuration doConfigure
    INFO: HHH000041: Configured SessionFactory: null
    Jul 23, 2016 5:08:12 PM 
    org.hibernate.service.jdbc.connections.
    internal.DriverManagerConnectionProviderImpl configure
    INFO: HHH000402: Using Hibernate built-in connection pool (not for 
    production use!)
    Jul 23, 2016 5:08:12 PM 
    org.hibernate.service.jdbc.connections.internal.
    DriverManagerConnectionProviderImpl configure
    INFO: HHH000115: Hibernate connection pool size: 1
    Jul 23, 2016 5:08:12 PM org.hibernate.service.jdbc.connections.internal.
    DriverManagerConnectionProviderImpl configure
    INFO: HHH000006: Autocommit mode: false
    Jul 23, 2016 5:08:12 PM org.hibernate.service.jdbc.connections.internal.
    DriverManagerConnectionProviderImpl configure
    INFO: HHH000401: using driver
    [com.mysql.jdbc.Driver] at URL [jdbc:mysql://127.0.0.1:3307/pankaj]
    Jul 23, 2016 5:08:12 PM 
    org.hibernate.service.jdbc.connections.internal.
    DriverManagerConnectionProviderImpl configure
    INFO: HHH000046: Connection properties: {user=root, password=****}
    Jul 23, 2016 5:08:12 PM org.hibernate.dialect.Dialect <init>
    INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
    Jul 23, 2016 5:08:12 PM org.hibernate.engine.transaction.internal.
    TransactionFactoryInitiator initiateService
    INFO: HHH000399: Using default transaction strategy 
    (direct JDBC transactions)
    Jul 23, 2016 5:08:12 PM org.hibernate.hql.internal.ast.
    ASTQueryTranslatorFactory <init>
    INFO: HHH000397: Using ASTQueryTranslatorFactory
    Jul 23, 2016 5:08:12 PM org.hibernate.tool.hbm2ddl.SchemaExport execute
    INFO: HHH000227: Running hbm2ddl schema export
    Hibernate: drop table if exists USER_DTLS
    Hibernate: create table USER_DTLS 
    (ID integer not null, address varchar(255), 
    Joined_Date datetime, User_Name varchar(255), primary key (ID))
    Jul 23, 2016 5:08:13 PM org.hibernate.tool.hbm2ddl.SchemaExport execute
    INFO: HHH000230: Schema export complete
    Hibernate: insert into USER_DTLS 
    (address, Joined_Date, User_Name, ID)    values (?, ?, ?, ?)

你可以看到它创建了一个表USER_DTLS
当它必须创建user_details时，我删除了用户详细信息中的2个字段，我留下了id＆amp; user_name尽管它显示4个字段 USER_DTLS（地址，Joined_Date，User_Name，ID）值（？，？，？，？）

任何人都可以帮助解决hibernate这种奇怪的行为吗？