035_一对一单向外键关联_annotation

星期六, 一月 09, 2016   17:59

一对一单向关联

1.a)hibernate_0700_One2One_unic_fk

b)Annotation: @OneToOne@JoinColumn

c)xml:<many-to-one/>

 

关系映射

对象

 

表与表之间的关系只有外键。

 

 

关系映射(这里讲的是对象)

 

关系对象的关系:

        一对一、一对多、多对多

 

写在对象里，又出现了单向、多向。

 

加起来7中。

 

一对一:

1.单向(主键、外键)

2.双向()

 

 

 

 

7.集合映射

8.继承关系

9.组件映射

 

 

2.简化问题

   2.1怎么写Annotation

   2.2增删改查CRUD怎么写

 

3.一对一

3.1单向(主键、外键)

3.2

 

 

 

 

 

本节:

一对一:

1.一对一单向、外键关联

 

步骤:

考虑这两个类怎么写

Husband  -----Wife

要在上面加上@Entity保证是实体类

 

站在husband角度有一个wife的引用

 

 

然后在数据库中进行设计表

两张表

husband    id name wife_id

wife           id  name

几种方法:

1.主键关联

2.外键关联

3.关联表-----多对多的时候使用

 

 

运行测试:

       在运行的console中看到自动帮你生成的建表语句，数据库中对应的表。

 

 

 

二、使用powerdesinger根据sql进行生成表

 

1.先数据库配置

数据库-->config    connection 

--->connection profile-->新加一个数据源

:name:  MySql  description:MySql....

还需要在环境变量中进行配置mysql.jar，因为powerdesigner支持不好

-----加了可还是没有成功。

 

 

代码案例:

 

package com.zhuhw.hibernate.model;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToOne;

@Entity
public class Husband{
	private int id;
	private String name;
	//一个husband里又一个wife的引用
    private Wife wife;
	@Id
	@GeneratedValue
	public int getId() {
		return id;
	}
	public String getName() {
		return name;
	}
	@OneToOne
	public Wife getWife() {
		return wife;
	}
	public void setId(int id) {
		this.id = id;
	}
	public void setName(String name) {
		this.name = name;
	}
	public void setWife(Wife wife) {
		this.wife = wife;
	}
}

 

 

package com.zhuhw.hibernate.model;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class Wife{
	private int id;
	private String name;
    @Id
    @GeneratedValue
	public int getId() {
		return id;
	}
	public String getName() {
		return name;
	}
	public void setId(int id) {
		this.id = id;
	}
	public void setName(String name) {
		this.name = name;
	}
}

 

 

 

 

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

        <!-- Database connection settings -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost/hibernate</property>
        <property name="connection.username">root</property>
        <property name="connection.password">root</property>

        
        <!--
        <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
        <property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property>
        <property name="connection.username">scoot</property>
        <property name="connection.password">tiger</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>

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

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

        <!-- Drop and re-create the database schema on startup -->
        <property name="hbm2ddl.auto">update</property>
      
	    <mapping class="com.zhuhw.hibernate.model.Husband"/>
		<mapping class="com.zhuhw.hibernate.model.Wife"/>	    
    </session-factory>

</hibernate-configuration>

 

 

 

 

package com.zhuhw.hibernate.model;

import java.util.Date;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class HibernateORMappingTest {
	
	public static SessionFactory sf = null;
	@BeforeClass
	public  static void beforeClass(){
			sf = new AnnotationConfiguration().configure().buildSessionFactory();
	}
	
	@Test
	public void testOne2One(){
		new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
	}
	@AfterClass
	public static void afterClass(){
		sf.close();
	}
	
	
	
}

 

 

ok刚开始运行不成功是没加@Entity

已解决