java - 为什么这个 String desc 变量没有在 hibernate 中插入到数据库中

Question

我是 hibernate 框架的新手。我正在关注此 link 上提供的教程系列.这是我的模型类

package kasun.hibernate.moreAnnotations;

import java.util.Date;

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

@Entity 
@Table(name="UserDetailsMoreAnn")
public class UserDetailsMoreAnnotations {
    private int id;
    private String name;
    private String address;
    private Date date;
    private String desc;

    @Id
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    public Date getDate() {
        return date;
    }
    public void setDate(Date date) {
        this.date = date;
    }
//  public String getDesc() {
//      return desc;
//  }
//  public void setDesc(String desc) {
//      this.desc = desc;
//  }





}

这是我的服务方法

package kasun.hibernate.moreAnnotations;

import java.util.Date;

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

public class ServiceMethod {
    public static void main(String[] args) {
        UserDetailsMoreAnnotations objct= new UserDetailsMoreAnnotations();
        objct.setName("Kalanka");
        objct.setId(7);
        objct.setAddress("Kuliyapitiya");
        objct.setDate(new Date());      // provide the current date
//      objct.setDesc("Younger Brother");



        SessionFactory sessionFactory=new Configuration().configure().buildSessionFactory();
        Session session= sessionFactory.openSession();
        session.beginTransaction();
        session.save(objct);
        session.getTransaction().commit();

    }

}

这是我的hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!-- ~ Hibernate, Relational Persistence for Idiomatic Java ~ ~ License: 
    GNU Lesser General Public License (LGPL), version 2.1 or later. ~ See the 
    lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>. -->
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

        <!-- Database connection settings -->
        <!-- <property name="connection.driver_class">org.hsq/ldb.jdbcDriver</property> 
            <property name="connection.url">jdbc:hsqldb:hsql://localhost/TestDB</property> -->

        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost:3306/HibernateTesting1</property>
        <property name="connection.username">root</property>
        <property name="connection.password"></property>

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">1</property>

        <!-- SQL dialect -->
        <property name="dialect">
            org.hibernate.dialect.MySQLDialect
        </property>

        <!-- Enable Hibernate's automatic session context management -->
        <property name="current_session_context_class">thread</property>

        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
        <property name="show_sql">true</property>

        <property name="hbm2ddl.auto">update</property>



        <!-- 5) for the kasun.hibernate.moreAnnotations package -->
        <mapping class="kasun.hibernate.moreAnnotations.UserDetailsMoreAnnotations" />




    </session-factory>

</hibernate-configuration>

以上代码运行没有错误。我遇到的问题是，当我取消注释这些行时

   public String getDesc() {
            return desc;
    }
        public void setDesc(String desc) {
        this.desc = desc;
        }

在我的 model class 中，通过取消注释行将值设置为 descobjct.setDesc("弟弟");在服务方法

我得到一个错误，因为 Unable to execute command [alter table UserDetailsMoreAnn add column desc varchar(255)] 它说 你的 SQL 语法有错误；查看与您的 MySQL 服务器版本对应的手册，了解在第 1 行的“desc varchar(255)”附近使用的正确语法。我做错了什么？谁能帮我解决这个问题。提前致谢

Answer 1

DESC是MySQL中的保留关键字，不能用于字段名。尝试重命名为 Description 或其他名称。 :)

您也可以注释该字段，但必须使用括号或转义引号:

@Column(name = "[DESC]")
公共(public)字符串 getDesc() {

或

@Column(name = "\"DESC\"")
公共(public)字符串 getDesc() {

MySQL 5.7 的保留字列表:https://dev.mysql.com/doc/refman/5.7/en/keywords.html