hibernate自动删除以前的表

2011-07-10 06:13:49 226 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

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<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

	<session-factory name="foo">

		<property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>

		<property name="hibernate.connection.url">jdbc:oracle:thin:@127.0.0.1:1521:test</property>

		<property name="hibernate.connection.username">test</property>

		<property name="hibernate.connection.password">test</property>

		<property name="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</property>

		<property name="hiernate.hbm2ddl.auto">validate</property>

		<property name="hibernate.show_sql">true</property>

		<mapping resource="com/asm/hibernate/domain/Student.hbm.xml"/>

		<mapping resource="com/asm/hibernate/domain/Teacher.hbm.xml"/> 

	</session-factory>

</hibernate-configuration>

这是我的hibernate.cfg.xml文件，不管我把hbm2ddl.auto配置成什么值，结果都会把以前建的表删除掉。我的java代表中并没有创建表的语句，请问这是为什么啊？？？？
小弟刚学hibernate，请大侠们帮帮忙，只用到hibernate，没有struts spring.

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lg_asus

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切换为时间正序

王莹月 2012-06-15

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你是成功了，哥杯具了，搞死了

lg_asus 2011-07-22

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时隔2周，无奈只能删除重建项目，这次竟然成功了

我都不知道为什么。。。

lg_asus 2011-07-10

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com.asm.hibernate.domain就是放java文件的包了，Teacher.hbm.xml和Student.hbm.xml是在这个包下

hibernate.cfg.xml是在src根目录下



public class Student {



	private int id;

	private String name ;

	private Set<Teacher> teachers;

	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 Set<Teacher> getTeachers() {

		return teachers;

	}

	public void setTeachers(Set<Teacher> teachers) {

		this.teachers = teachers;

	}

	

}

上面的是Student.java,Teacher.java和这一样。
测试代码：



s = HibernateUtil.getSession();

			tr = s.beginTransaction();

			Teacher t1 = new Teacher();

			t1.setName("t1Name");

			Teacher t2 = new Teacher();

			t2.setName("t2Name");

			Student s1 = new Student();

			s1.setName("s1Name");

			Student s2 = new Student();

			s2.setName("s2Name");

			Set<Teacher> ts = new HashSet<Teacher>();

			ts.add(t1);

			ts.add(t2);

			Set<Student> ss = new HashSet<Student>();

			ss.add(s1);

			ss.add(s2);

			t1.setStudents(ss);

			t2.setStudents(ss);

			//s1.setTeachers(ts);

			//s2.setTeachers(ts);

			s.save(s1);

			s.save(s2);

			s.save(t1);

			s.save(t2);

			tr.commit();

控制台上显示的sql信息：
drop table Student cascade constraints
drop table Teacher cascade constraints
drop table teacher_student cascade constraints
drop sequence hibernate_sequence
create table Student (id number(10,0) not null, name varchar2(255 char), primary key (id))
create table Teacher (id number(10,0) not null, name varchar2(255 char), primary key (id))
create table teacher_student (student_id number(10,0) not null, teacher_id number(10,0) not null, primary key (teacher_id, student_id))
alter table teacher_student add constraint FK2E2EF2DEA1548DAC foreign key (teacher_id) references Teacher
alter table teacher_student add constraint FK2E2EF2DE90B9430C foreign key (student_id) references Student
create sequence hibernate_sequence
Hibernate: select hibernate_sequence.nextval from dual
Hibernate: select hibernate_sequence.nextval from dual
Hibernate: select hibernate_sequence.nextval from dual
Hibernate: select hibernate_sequence.nextval from dual
Hibernate: insert into Student (name, id) values (?, ?)
Hibernate: insert into Student (name, id) values (?, ?)
Hibernate: insert into Teacher (name, id) values (?, ?)
Hibernate: insert into Teacher (name, id) values (?, ?)
Hibernate: insert into teacher_student (teacher_id, student_id) values (?, ?)
Hibernate: insert into teacher_student (teacher_id, student_id) values (?, ?)
Hibernate: insert into teacher_student (teacher_id, student_id) values (?, ?)
Hibernate: insert into teacher_student (teacher_id, student_id) values (?, ?)
每次都是这样的sql信息

lg_asus 2011-07-10

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to 1L:这些值含义我都知道啊，问题就是我无论设置成何值都会删除表。。。

附上其它的代码吧：
Student.hbm.xml:

<?xml version="1.0" encoding="UTF-8"?>

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

<hibernate-mapping package="com.asm.hibernate.domain">

	<class name="Student">

		<id name="id">

			<generator class="native"></generator>

		</id>

		<property name="name"></property>

		<set name="teachers" table="teacher_student">

			<key column="student_id"/>

			<many-to-many class="Teacher" column="teacher_id"></many-to-many>

		</set>

	</class>

</hibernate-mapping>

Teacher.hbm.xml:

<?xml version="1.0" encoding="UTF-8"?>

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

<hibernate-mapping package="com.asm.hibernate.domain">

	<class name="Teacher">

		<id name="id">

			<generator class="native"></generator>

		</id>

		<property name="name"></property>

		<set name="students" table="teacher_student">

			<key column="teacher_id"/>

			<many-to-many class="Student" column="student_id"></many-to-many>

		</set>

	</class>

</hibernate-mapping>

每次执行都会：
drop table Student cascade constraints
drop table Teacher cascade constraints
drop table teacher_student cascade constraints
drop sequence hibernate_sequence、
连hibernate_sequence都删除并重建了。真的不可思议。。
开发环境是eclipse，只用到了hibernate，如果要源码的话可以提供

soo520 2011-07-10

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hibernate自动删除以前的表

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