副标题#e#
1 多对一
第一步 :成立工具模子
User
—————————–
id:int
name:String
group:Group
Group
——————————
id:int
name:String
第二步:映射文件
Xml代码
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="User" table="t_user">
<id name="id" column="id">
<generator class="identity"/>
</id>
<property name="name" column="User_name" unique="true"/>
<many-to-one name="group" column="groupid"/>
</class>
</hibernate-mapping>
2 一对一映射
#p#副标题#e#
2.1 主键映射
1. 成立工具模子
Person[id-int,name-String]
IdCard[id-int,cardNo-int]
2. 映射文件
Xml代码
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="Person" table="t_person">
<id name="id">
<generator class="foreign">
<param name="property">idCard</param>
</generator>
</id>
<property name="name" column="Person_name" />
<one-to-one name="idCard" constrained="true"/>
</class>
</hibernate-mapping>
2.2 主键映射双向
只需要在IdCard 的XML中添加<one-to-one>标签指向person,就可以 汇报Hibernate如何加载person,默认凭据主键加载
2.3 外键关联映射
1. 工具模子
Person[id-int,name-String,idcard-IdCard]
IdCard[id-int,cardNo-int]
2 mapping文件
Xml代码
Person.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="Person" table="t_person">
<id name="id">
<generator class="identity">
</generator>
</id>
<property name="name" column="Person_name" />
<many-to-one name="idCard" unique="true"></many-to- one>
</class>
</hibernate-mapping>
2.4 one-to-one 外键双向mapping
只需要在另一端(IdCard)插手<one-to-one>标签,可是hibernate默 认凭据主键加载,所以要汇报hibernate凭据指定列来加载
示意:
Xml代码
Id-card
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="IdCard" table="t_idcard">
<id name="id" column="id">
<generator class="identity"/>
</id>
<property name="cardNo" column="cardno" />
<one-to-one name="person" property-ref="idCard"></one-to- one>
</class>
</hibernate-mapping>
3 一对多映射
1 成立工具模子
Classes[id-int,name-String,student-Set]
Student[id-int,name-String]
2 映射文件
Xml代码
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="Class" table="t_class">
<id name="id">
<generator class="native"/>
</id>
<property name="name" />
<set name="student" >
<key column="classid" />
<one-to-many class="Student"/>
</set>
</class>
</hibernate-mapping>
#p#分页标题#e#
缺点:若将Student的classid配置为非空,将无法生存。应为不是student这 一端维护干系,所以student不知道是哪个班级,所以需要发出多余的update语 句来更新干系。
(一对多): 先要session.sava(学生),再sessio.save(班级)
(多对一): 先要session.sava(班级),再sessio.save(学生)
改造 回收 一对多双向关联
Xml代码
<set name="student" inverse="true">
<set name="student" inverse="true">
这样的长处是 存入数据让多的一端举办维护,不需要发出多余的 update.
4 多对多mapping
单向(回收第三方表)
1 工具模子
Role[id-int,name-String]
User[id-int,name-String,role-Set]
2映射文件
Xml代码
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="User" table="t_user">
<id name="id">
<generator class="native"/>
</id>
<property name="name" />
<set name="role" table="t_user_role">
<key column="userid"></key>
<many-to-many class="Role" column="roleid" />
</set>
</class>
</hibernate-mapping>
双向:
1 工具模子:
Role[id-int,name-String,user-Set]
User[id-int,name-String,role-Set]
2 mapping文件:
Xml代码
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="Role" table="t_role">
<id name="id">
<generator class="native"/>
</id>
<property name="name" />
<set name="user" table="t_user_role">
<key column="userid"></key>
<many-to-many class="User" column="userid" />
</set>
</class>
</hibernate-mapping>
5 担任mapping
第一类担任映射
1 工具模子
Animal
private int id
private String name
private Boolean sex
--------------------------------------------------
public class Bird extends Animal
private int height
--------------------------------------------------
public class Pig extends Animal
private int weight
2 mapping 文件
Xml代码
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="Animal" table="t_animal" >
<id name="id" >
<generator class="native"/>
</id>
<discriminator column="type" type="string"></discriminator>
<property name="name"/>
<property name="sex"/>
<subclass name="Pig" discriminator-value="P">
<property name="weight"/>
</subclass>
<subclass name="Bird" discriminator-value="B">
<property name="height"/>
</subclass>
</class>
</hibernate-mapping>
第二类mapping
1 工具模子
2 mapping 文件
Xml代码
#p#分页标题#e#
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="Animal" table="t_animal" >
<id name="id" >
<generator class="native"/>
</id>
<property name="name"/>
<property name="sex"/>
<joined-subclass name="Pig" table="t_pig">
<key column="pid"/>
<property name="weight"/>
</joined-subclass>
<joined-subclass name="Bird" table="t_bird">
<key column="bid"/>
<property name="height"/>
</joined-subclass>
</class>
</hibernate-mapping>
3 第三类mapping
1工具模子
2 mapping 文件
Xml代码
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="Animal" table="t_animal" >
<id name="id" >
<generator class="native"/>
</id>
<property name="name"/>
<property name="sex"/>
<union-subclass name="Pig" table="t_pig">
<property name="weight"/>
</union-subclass>
<union-subclass name="Bird" table="t_bird">
<property name="height"/>
</union-subclass>
</class>
</hibernate-mapping>
6 Component 映射
component不是实体,没有OID。
1 工具模子
public class Employee
private int id
private String name
private Contact contact
-------------------------------------
public class Contact
private String email
private String address
private String zipcode
private String contactTel
-------------------------------------
public class User
private int id
private String name
private Contact contact
2 mapping文件
Xml代码
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="User" table="t_user" >
<id name="id" >
<generator class="native"/>
</id>
<property name="name"/>
<component name="contact">
<property name="email"></property>
<property name="address"></property>
<property name="zipcode"></property>
<property name="contactTel"></property>
</component>
</class>
</hibernate-mapping>
7 复合主键mapping
凡是将复合主键相关属性,单独放到一个类中
这个类必需实现 Serializable接口
这个类必需重写hashCode()和equals()要领
XML
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.nintenyun.hibernate">
<class name="SC" table="t_sc" >
<composite-id name="scpk">
<key-property name="sno"/>
<key-property name="cno"/>
</composite-id>
<property name="sname"></property>
<property name="cname"></property>
</class>
</hibernate-mapping>