Hibernate的学习总结(数据关联)

 Hibernate中的数据关联主要分为三大类：

1对1： 一个人对应一个身份证

1对多，多对1：  一个人有很多联系地址 ，多个用户拥有一个权限

多对多：  一个学生可以对应选很多门课，一门课可以对应有许多学生

 

一.1对1关系 --主键关联

一个人对应一个身份证

表结构：

-- 创建表
CREATE TABLE person
(
 id VARCHAR(32) NOT NULL PRIMARY KEY ,
 name VARCHAR(20) NOT NULL ,
 age int
) ;
CREATE TABLE idcard
(
 id VARCHAR(32) ,
 serial VARCHAR(18) NOT NULL ,
 expiry int ,
 FOREIGN KEY(id) REFERENCES person(id) ON DELETE CASCADE
) ;

 

Person.java

public class Person {private String id ;private String name ;private Integer age ;private IDCard idCard ;public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public IDCard getIdCard() {return idCard;}public void setIdCard(IDCard idCard) {this.idCard = idCard;}}

 

IDCard.java

public class IDCard {private String id ;private String serial;private Integer expiry;private Person person;public Integer getExpiry() {return expiry;}public void setExpiry(Integer expiry) {this.expiry = expiry;}public String getSerial() {return serial;}public void setSerial(String serial) {this.serial = serial;}public Person getPerson() {return person;}public void setPerson(Person person) {this.person = person;}public String getId() {return id;}public void setId(String id) {this.id = id;}}

 

Person.hbm.xml 关联主表

<?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="org.lxh.hibernate.demo04.pojo.Person" table="person"><id name="id" type="java.lang.String"><column name="id" length="32" /><generator class="uuid.hex"></generator></id><property name="name" type="java.lang.String"><column name="name" length="20" not-null="true" /></property><property name="age" type="java.lang.Integer"><column name="age" /></property><one-to-one name="idCard"class="org.lxh.hibernate.demo04.pojo.IDCard" cascade="all"outer-join="true"></one-to-one></class></hibernate-mapping>

 

 

Idcard.hbm.xml 关联从表

<?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="org.lxh.hibernate.demo04.pojo.IDCard" table="idcard"><id name="id" column="id" type="java.lang.String"><generator class="foreign"><param name="property">person</param></generator></id><one-to-one name="person"class="org.lxh.hibernate.demo04.pojo.Person" constrained="true"></one-to-one><property name="serial" type="java.lang.String"><column name="serial" length="18" not-null="true" /></property><property name="expiry" type="java.lang.Integer"><column name="expiry" not-null="true" /></property></class></hibernate-mapping>

 

插入代码示例：

PersonIDCardOperation po = new PersonIDCardOperation();// 设置人的信息Person per = new Person() ;per.setName("lxh");per.setAge(new Integer(20));// 设置身份证信息IDCard ic = new IDCard();ic.setSerial("888888888888888");ic.setExpiry(12);per.setIdCard(ic);ic.setPerson(per);po.insert(per) ;

 

二. 1对多，多对1关系 --外键关联

1.1对多关系

 一个人有很多联系地址

表结构

CREATE TABLE person
(
 pid VARCHAR(32) NOT NULL PRIMARY KEY ,
 name VARCHAR(20) NOT NULL ,
 age INT
) ;

CREATE TABLE address
(
 aid VARCHAR(32) NOT NULL PRIMARY KEY ,
 name VARCHAR(50) NOT NULL ,
 zipcode VARCHAR(10) NOT NULL ,
 pid VARCHAR(32) ,
 FOREIGN KEY (aid) REFERENCES person(pid) ON DELETE CASCADE
) ;

 

Person.java

import java.util.Set;public class Person {private String pid ;private String name ;private int age ;private Set address ;public Set getAddress() {return address;}public void setAddress(Set address) {this.address = address;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPid() {return pid;}public void setPid(String pid) {this.pid = pid;}}

 

Address.java

public class Address {private String aid ;private String name ;private String zipcode ;private Person person ;public String getAid() {return aid;}public void setAid(String aid) {this.aid = aid;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Person getPerson() {return person;}public void setPerson(Person person) {this.person = person;}public String getZipcode() {return zipcode;}public void setZipcode(String zipcode) {this.zipcode = zipcode;}}

 

Person.hbm.xml  关联主表

<?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="org.lxh.hibernate.demo06.pojo.Person" table="person"catalog="mldn"><id name="pid" type="java.lang.String"><column name="pid" length="32" /><generator class="uuid.hex"></generator></id><property name="name" type="java.lang.String"><column name="name" length="20" not-null="true" /></property><property name="age" type="java.lang.Integer"><column name="age" /></property><set name="address" table="address" cascade="all" inverse="true"><key> <column name="pid" length="32" /></key><one-to-many class="org.lxh.hibernate.demo06.pojo.Address" /></set></class></hibernate-mapping>

 

Address.hbm.xml 关联从表

<?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="org.lxh.hibernate.demo06.pojo.Address" table="address" catalog="mldn"> <id name="aid" type="java.lang.String"> <column name="aid" length="32" /> <generator class="uuid.hex"></generator> </id> <many-to-one name="person" class="org.lxh.hibernate.demo06.pojo.Person"> <column name="pid" length="32" /> </many-to-one> <property name="name" type="java.lang.String"> <column name="name" length="50" not-null="true" /> </property> <property name="zipcode" type="java.lang.String"> <column name="zipcode" length="10" not-null="true" /> </property> </class></hibernate-mapping>

 

 2.多对一关系

多个用户拥有一个权限

 

表结构

-- 创建表
CREATE TABLE person
(
 id VARCHAR(32) PRIMARY KEY NOT NULL ,
 name VARCHAR(20) NOT NULL ,
 age INT ,
 gid VARCHAR(32)
) ;

 

CREATE TABLE TGROUP
(
 gid VARCHAR(32) PRIMARY KEY NOT NULL,
 name VARCHAR(20)
) ;

 

Person.java

public class Person {private String id ;private String name ;private int age ;private TGroup tgroup ;public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public TGroup getTgroup() {return tgroup;}public void setTgroup(TGroup tgroup) {this.tgroup = tgroup;}}

 

TGroup.java

public class TGroup {private String gid ;private String name ;private Person person ;public String getName() {return name;}public void setName(String name) {this.name = name;}public Person getPerson() {return person;}public void setPerson(Person person) {this.person = person;}public String getGid() {return gid;}public void setGid(String gid) {this.gid = gid;}}

 

Person.hbm.xml 关联主表

<?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="org.lxh.hibernate.demo05.pojo.Person" table="person"><id name="id" type="java.lang.String"><column name="id" length="32" /><generator class="uuid.hex"></generator></id><property name="name" type="java.lang.String"><column name="name" length="20" not-null="true" /></property><property name="age" type="java.lang.Integer"><column name="age" /></property><many-to-one name="tgroup"class="org.lxh.hibernate.demo05.pojo.TGroup" column="gid"unique="true"></many-to-one></class></hibernate-mapping>

 

TGroup.hbm.xml 关联从表

<?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="org.lxh.hibernate.demo05.pojo.TGroup" table="tgroup"><id name="gid" type="java.lang.String"><column name="gid" length="32" /><generator class="uuid.hex"></generator></id><property name="name" type="java.lang.String"><column name="name" length="20" not-null="true" /></property><one-to-one name="person"class="org.lxh.hibernate.demo05.pojo.Person" property-ref="tgroup"></one-to-one></class></hibernate-mapping>

 

一对多是将映射关系写在一的一端，多对一是将映射关系写在多的一端。一对多和多对一的映射策略是一致的，都是通过在"多"的一端添加一个外键指向"一"的一端，只是站的角度不同。

不管多对一还是一对多，都是在"多"的一端添加一个外键指向"一"的一端，只不过是多对一是在多的一端为其自己添外键，而一对多则是在一的一端为多的一端添加外主键。

 

 

3.多对多关系

一个学生可以对应选很多门课，一门课可以对应有许多学生

 

表结构

CREATE TABLE person
(
 pid VARCHAR(32) NOT NULL PRIMARY KEY ,
 name VARCHAR(20) NOT NULL ,
 age INT
) ;
CREATE TABLE server
(
 sid VARCHAR(32) NOT NULL PRIMARY KEY ,
 name VARCHAR(20) NOT NULL
) ;
CREATE TABLE person_server
(
 pid VARCHAR(32) ,
 sid VARCHAR(32) ,
 FOREIGN KEY (pid) REFERENCES person(pid) ON DELETE CASCADE ,
 FOREIGN KEY (sid) REFERENCES server(sid) ON DELETE CASCADE
) ;

 

Person.java

public class Person {private String pid ;private String name ;private int age ;private Set servers ;public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPid() {return pid;}public void setPid(String pid) {this.pid = pid;}public Set getServers() {return servers;}public void setServers(Set servers) {this.servers = servers;}}

 

Server.java

import java.util.Set;public class Server {private String sid ;private String name ;private Set persons ;public String getName() {return name;}public void setName(String name) {this.name = name;}public Set getPersons() {return persons;}public void setPersons(Set persons) {this.persons = persons;}public String getSid() {return sid;}public void setSid(String sid) {this.sid = sid;}}

 

Person.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="org.lxh.hibernate.demo07.pojo.Person" table="person"><id name="pid" type="java.lang.String"><column name="pid" length="32" /><generator class="uuid.hex"></generator></id><property name="name" type="java.lang.String"><column name="name" length="20" not-null="true" /></property><property name="age" type="java.lang.Integer"><column name="age" /></property><set name="servers" table="person_server" cascade="all"><key column="pid"></key><many-to-many class="org.lxh.hibernate.demo07.pojo.Server"column="sid"></many-to-many></set></class></hibernate-mapping>

 

Server.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="org.lxh.hibernate.demo07.pojo.Server" table="server"> <id name="sid" type="java.lang.String"> <column name="sid" length="32" /> <generator class="uuid.hex" /> </id> <property name="name" type="java.lang.String"> <column name="name" length="20" not-null="true" /> </property> <set name="persons" table="person_server" cascade="all"><key column="sid"></key><many-to-many class="org.lxh.hibernate.demo07.pojo.Person"column="pid"></many-to-many></set> </class></hibernate-mapping>