Hibernate继承映射

1、hibernate继承映射hibernate继承映射 继承是面对对象编程中一个很重要的特征，在做面对对象的分析与设计是，常常会设计出详细继承关联的持久化类。 持久化类 employee类 public class employee private int ; private sing name; private department depart; public department getdepart() return depart; public void depart(department depart) this.depart = depart; public int getid()

2、return id; public void setid(int id) this.id = id; public string getname() return name; public void setname(string name) = name; ser类 public class skiller tends employee private string ; public string getskill() return skill; public void setskill(string skill) this.skill = skill; sales类 pu

3、blic class sales extends employee private int sell; public int getsell() return sell; public void setsell(int sell) this.sell = sell; 方式一：囫囵的继承体系就用一张表。设计一张表employee employee.hbm.xml文件 ?xml version= 1.0 ? !doctype hibernate-map public -/hibernate/hibernate mapping dtd 3.0/en /d

4、td/hibernate-mapping-3.0.dtd hibernate-mapping package= com.hbsi.domain class name= employee table= employee discriminator-value= 0 id name= id umn= id generator /id discriminator column= type type= int / property name= name column= name / many-to-one name= depart column= depart_id / bclass name= sk

5、iller discriminator-value= 1 property name= skill / /subclass subclass name= sales discriminator-value= 2 property name= sell / /subclass /class /hibernate-mapping 方式二：每个子类一张表，存放子类所特有的属性 employee.hbm.xml文件 ?xml version= 1.0 ? !doctype hibernate-mapping public -/hibernate/hibernate mapping dtd 3.0/en

6、 /dtd/hibernate-mapping-3.0.dtd hibernate-mapping package= com.hbsi.domain class name= employee table= employee id name= id generator /id property name= name column= name / many-to-one name= depart column= depart_id / -subclass name= skiller table= skiller key column= employee

7、_id / property name= skill / /joined-subclass joined-subclass name= sales table= sales key column= employee_id / property name= sell / /joined-subclass /class /hibernate-mapping 方式三：混合用法“一个类继承体系一张表”和“每个子类一张表” employee.hbm.xml文件 ?xml version= 1.0 ? !doctype hibernate-mapping public -/hibernate/hibern

8、ate mapping dtd 3.0/en /dtd/hibernate-mapping-3.0.dtd hibernate-mapping package= com.hbsi.domain class name= employee table= employee discriminator-value= 0 id name= id generator /id discriminator column= type type= int / property name= name column= name / many-to-one name= de

9、part column= depart_id / subclass name= skiller discriminator-value= 1 property name= skill / /subclass subclass join table= sales key column= employee_id / property name= sell / /join /subclass /class /hibernate-mapping 方式四：每个详细类一张表(union-subclass) ，保存是子类完整信息 employee.hbm.xml文件 ?xml version= 1.0 ?

10、!doctype hibernate-mapping public -/hibernate/hibernate mapping dtd 3.0/en /dtd/hibernate-mapping-3.0.dtd hibernate-mapping package= com.hbsi.domain class name= employee table= employee id name= id generator /id property name= name column= name / many-to-one name= depart column= depart_id / union-subclass name= skiller table= s