hibernate-----many-to-many

2008 - 01 - 25

hibernate-----many-to-many

CREATE DATABASE `manytomany`
CHARACTER SET 'utf8';

USE `manytomany`;

DROP TABLE IF EXISTS `student`;
create table student(
    sid int auto_increment primary key,
    name varchar(10) not null
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
DROP TABLE IF EXISTS `teacher`;
create table teacher(
    tid int auto_increment primary key,
    name varchar(10) not null
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
DROP TABLE IF EXISTS `st`;
create table st(
    sid int not null,
    tid int not null
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE DATABASE `manytomany`
CHARACTER SET 'utf8';

USE `manytomany`;

DROP TABLE IF EXISTS `student`;
create table student(
	sid int auto_increment primary key,
	name varchar(10) not null
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
DROP TABLE IF EXISTS `teacher`;
create table teacher(
	tid int auto_increment primary key,
	name varchar(10) not null
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
DROP TABLE IF EXISTS `st`;
create table st(
	sid int not null,
	tid int not null
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

Teacher.java

package com.test.domain;

import java.util.HashSet;
import java.util.Set;

public class Teacher implements java.io.Serializable {

    private Integer tid;

    private String name;

    private Set students = new HashSet();

    public Teacher() {
    }

    public Teacher(String name) {
        this.name = name;
    }

    public Integer getTid() {
        return this.tid;
    }

    public void setTid(Integer tid) {
        this.tid = tid;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Set getStudents() {
        return students;
    }

    public void setStudents(Set students) {
        this.students = students;
    }



}

package com.test.domain;

import java.util.HashSet;
import java.util.Set;

public class Teacher implements java.io.Serializable {

	private Integer tid;

	private String name;
	
	private Set students = new HashSet();
	
	public Teacher() {
	}

	public Teacher(String name) {
		this.name = name;
	}

	public Integer getTid() {
		return this.tid;
	}

	public void setTid(Integer tid) {
		this.tid = tid;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Set getStudents() {
		return students;
	}

	public void setStudents(Set students) {
		this.students = students;
	}
	
	

}

Student.java:

package com.test.domain;

import java.util.HashSet;
import java.util.Set;

public class Student implements java.io.Serializable {

    private Integer sid;

    private String name;

    private Set teachers = new HashSet();

    public Student() {
    }

    public Student(String name) {
        this.name = name;
    }

    public Integer getSid() {
        return this.sid;
    }

    public void setSid(Integer sid) {
        this.sid = sid;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Set getTeachers() {
        return teachers;
    }

    public void setTeachers(Set teachers) {
        this.teachers = teachers;
    }


}

package com.test.domain;

import java.util.HashSet;
import java.util.Set;

public class Student implements java.io.Serializable {

	private Integer sid;

	private String name;
	
	private Set teachers = new HashSet();

	public Student() {
	}

	public Student(String name) {
		this.name = name;
	}

	public Integer getSid() {
		return this.sid;
	}

	public void setSid(Integer sid) {
		this.sid = sid;
	}

	public String getName() {
		return this.name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Set getTeachers() {
		return teachers;
	}

	public void setTeachers(Set teachers) {
		this.teachers = teachers;
	}

	
}

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>
    <class name="com.test.domain.Teacher" table="teacher" catalog="manytomany">
        <id name="tid" type="java.lang.Integer">
            <column name="tid" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="name" length="10" not-null="true" />
        </property>
        <!--inverse="false": 由teacher操作student -->
        <set name="students" table="st" cascade="save-update" inverse="false">
            <key column="tid"></key>
            <many-to-many class="com.test.domain.Student" column="sid">
            </many-to-many>
        </set>
    </class>
</hibernate-mapping>

<?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>
    <class name="com.test.domain.Teacher" table="teacher" catalog="manytomany">
        <id name="tid" type="java.lang.Integer">
            <column name="tid" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="name" length="10" not-null="true" />
        </property>
        <!--inverse="false": 由teacher操作student -->
        <set name="students" table="st" cascade="save-update" inverse="false">
        	<key column="tid"></key>
        	<many-to-many class="com.test.domain.Student" column="sid">
        	</many-to-many>
        </set>
    </class>
</hibernate-mapping>

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>
    <class name="com.test.domain.Student" table="student" catalog="manytomany">
        <id name="sid" type="java.lang.Integer">
            <column name="sid" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="name" length="10" not-null="true" />
        </property>
        <!--inverse="true": 由teacher操作student -->
        <set name="teachers" table="st" cascade="save-update" inverse="true">
            <key column="sid"></key>
            <many-to-many class="com.test.domain.Teacher" column="tid">
            </many-to-many>
        </set>
    </class>
</hibernate-mapping>

<?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>
    <class name="com.test.domain.Student" table="student" catalog="manytomany">
        <id name="sid" type="java.lang.Integer">
            <column name="sid" />
            <generator class="native" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="name" length="10" not-null="true" />
        </property>
        <!--inverse="true": 由teacher操作student -->
        <set name="teachers" table="st" cascade="save-update" inverse="true">
        	<key column="sid"></key>
        	<many-to-many class="com.test.domain.Teacher" column="tid">
        	</many-to-many>
        </set>
    </class>
</hibernate-mapping>

测试类,Test.java

package com.test.dao;

import org.hibernate.Session;

import com.test.domain.Student;
import com.test.domain.Teacher;

public class Test {

    public static void main(String[] args) {
        Session session = HibernateSessionFactory.getSession();

        Teacher teacher1 = new Teacher();
        teacher1.setName("teacher1");

        Teacher teacher2 = new Teacher();
        teacher2.setName("teacher2");

        Teacher teacher3 = new Teacher();
        teacher3.setName("teacher3");

        Student student1 = new Student();
        student1.setName("student1");

        Student student2 = new Student();
        student2.setName("student2");
        //student1.getTeachers().add(teacher1);student1.getTeachers().add(teacher2);student2.getTeachers().add(teacher1);这几句代码可以不要，因为Teacher掌握主动权。所以下面几句代码给注释掉了
//      //学生一有2个老师
//      student1.getTeachers().add(teacher1);
//      student1.getTeachers().add(teacher2);
//
//      //学生二有一个老师
//      student2.getTeachers().add(teacher1);

        //因为老师是inverse="false" ,老师掌握主动权
        //第一个老师有2个学生
        teacher1.getStudents().add(student1);
        teacher1.getStudents().add(student2);

        //第二个老师有一个学生
        teacher2.getStudents().add(student1);

        session.saveOrUpdate(teacher1);
        session.saveOrUpdate(teacher2);
        session.beginTransaction().commit();
        session.close();

        /**执行的sql
        Hibernate: insert into manytomany.teacher (name) values (?)
        Hibernate: insert into manytomany.student (name) values (?)
        Hibernate: insert into manytomany.student (name) values (?)
        Hibernate: insert into manytomany.teacher (name) values (?)
        Hibernate: insert into st (tid, sid) values (?, ?)
        Hibernate: insert into st (tid, sid) values (?, ?)
        Hibernate: insert into st (tid, sid) values (?, ?)
        */

    }

}