为什么hbm2ddl.auto'update'属性不起作用或它如何起作用? [英] Why hbm2ddl.auto 'update' property is not working or how does it works?

问题描述

我是Hibernate的新手，据我所知，当hbm2ddl.auto设置为'update'时，它应该创建一个表(如果它不存在)，它应该自动创建一个新列，如果新的'property'列的标记已添加到映射文件中.正确的? 但是，每当我尝试运行我的课程时，它都会抛出表或视图不存在"而不是创建它.我正在使用休眠v5.10

I am new to Hibernate, As per my knowledge, when hbm2ddl.auto is set to 'update', it should create a table if its doesn't exist, it should create a new column automatically if the new 'property' tag for column is added in mapping file. Right? But whenever i am trying to run my class, it is throwing "Table or view doesn't exist" instead of creating it. I am using hibernate v5.10

这是我要运行的我的POC示例.预先感谢.

Here's my POC example i am trying to run. Thanks in advance.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
  <class name="com.nt.domain.Customer" table="CUSTOMER">
   <id name="custNo" length="10" type="int" column="CUSTNO"/>           
   <property name="customerName" length="20" type="string" column="CUSTNAME"/>
   <property name="billAmt" length="10" type="int" column="BILLAMT"/>
  </class>
</hibernate-mapping>

配置

<?xml version="1.0" encoding="UTF-8"?>
<!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>
    <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
    <property name="connection.url">jdbc:oracle:thin:@localhost:1521:sys</property>
    <property name="connection.username">Asif123</property>
    <property name="connection.password">Asif123</property>     
    <property name="show_sql">true</property>
    <property name="format_sql">true</property>
    <property name="use_sql_comments">true</property>
    <property name="dialect">org.hibernate.dialect.Oracle12cDialect</property>
    <property name="hbm2ddl.auto">update</property>
    <mapping resource="com/nt/domain/customer.hbm.xml"/>
</session-factory>

package com.nt.test;

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

import com.nt.domain.Customer;

public class UpdateTest {
  public static void main(String[] args) {
    Configuration cfg = new Configuration().configure();
    SessionFactory factory = cfg.buildSessionFactory();
    Session ses= factory.openSession();
    Transaction tx= ses.beginTransaction();

    Customer customer = new Customer();
    customer.setCustNo(101);
    customer.setCustomerName("Asif");
    customer.setBillAmt(1245);


    ses.save(customer);     
    tx.commit();

    ses.close();
    factory.close();
  }
}

客户

package com.nt.domain;

public class Customer {
  int custNo;
  String customerName;
  int billAmt;

//All getters and setters

} 

异常

Caused by: java.sql.SQLSyntaxErrorException: ORA-00942: table or view does not exist

at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:450)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:399)
at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:1059)
....

推荐答案

对于仍在寻找答案的任何人，如果您想体验更新"属性的所有功能，例如自动创建表，自动添加列(两种情况， :如果尚不可用)，则选择5.0.1.Final版本，它是支持它们的最稳定的版本.

For anyone still searching for an answer, If you want to experience all the functionalities of "update" property like auto table creation, auto adding of columns (both case : if already not available), then go for the 5.0.1.Final version, it is the most stable version supporting them.

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