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/>
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关系映射
对象
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表与表之间的关系只有外键。
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关系映射(这里讲的是对象)
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关系对象的关系:
? ? ? ? 一对一、一对多、多对多
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写在对象里，又出现了单向、多向。
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加起来7中。
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一对一:
1.单向(主键、外键)
2.双向()
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7.集合映射
8.继承关系
9.组件映射
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2.简化问题
? ?2.1怎么写Annotation
? ?2.2增删改查CRUD怎么写
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3.一对一
3.1单向(主键、外键)
3.2
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本节:
一对一:
1.一对一单向、外键关联
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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
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站在husband角度有一个wife的引用
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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
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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。
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二、使用powerdesinger根据sql进行生成表
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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。
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代码案例:
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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;
}
}
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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;
}
}
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<?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>
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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();
}
}
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ok刚开始运行不成功是没加@Entity
已解决
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原文：http://yuzhouxiner.iteye.com/blog/2270042