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多表分析和创建
一对一
类的创建
实例 |
原则 |
在夫类里面有一个妻类的对象 |
在任意一方都有对方的对象引用 |
在妻类里面有一个夫类的对象 |
在任意一方都有对方的对象引用 |
数据库表的创建
默认创建表结构
一对多
实体类的创建
实例 |
原则 |
在客户类中有联系人类的集合 |
在一的一方有多的一方的集合 |
在联系人类中有客户的对象 |
在多的一方有一的一方的对象 |
数据库表的创建
在多的一方创建一个字段,这个字段作为外键,指向一的一方的主键
多对多
实体类的创建
实例 |
原则 |
在用户类中有角色类的集合 |
在任意一方都需要有对方的集合 |
在角色类中有用户类的集合 |
在任意一方都需要有对方的集合 |
数据库表的创建
创建一张中间表,这个中间表里至少需要2个字段,让这2个字段当成是外键,指向各自表的主键
一对多关系映射
准备
创建客户表
CREATE TABLE `cst_customer` (
`cust_id` bigint(32) NOT NULL AUTO_INCREMENT COMMENT '客户编号(主键)',
`cust_name` varchar(32) NOT NULL COMMENT '客户名称(公司名称)',
`cust_source` varchar(32) DEFAULT NULL COMMENT '客户信息来源',
`cust_industry` varchar(32) DEFAULT NULL COMMENT '客户所属行业',
`cust_level` varchar(32) DEFAULT NULL COMMENT '客户级别',
`cust_address` varchar(128) DEFAULT NULL COMMENT '客户联系地址',
`cust_phone` varchar(64) DEFAULT NULL COMMENT '客户联系电话',
PRIMARY KEY (`cust_id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
创建联系人表
CREATE TABLE `cst_linkman` (
`lkm_id` bigint(32) NOT NULL AUTO_INCREMENT COMMENT '联系人编号(主键)',
`lkm_name` varchar(16) DEFAULT NULL COMMENT '联系人姓名',
`lkm_cust_id` bigint(32) NOT NULL COMMENT '客户id',
`lkm_gender` char(1) DEFAULT NULL COMMENT '联系人性别',
`lkm_phone` varchar(16) DEFAULT NULL COMMENT '联系人办公电话',
`lkm_mobile` varchar(16) DEFAULT NULL COMMENT '联系人手机',
`lkm_email` varchar(64) DEFAULT NULL COMMENT '联系人邮箱',
`lkm_qq` varchar(16) DEFAULT NULL COMMENT '联系人qq',
`lkm_position` varchar(16) DEFAULT NULL COMMENT '联系人职位',
`lkm_memo` varchar(512) DEFAULT NULL COMMENT '联系人备注',
PRIMARY KEY (`lkm_id`),
KEY `FK_cst_linkman_lkm_cust_id` (`lkm_cust_id`),
CONSTRAINT `FK_cst_linkman_lkm_cust_id` FOREIGN KEY (`lkm_cust_id`) REFERENCES `cst_customer` (`cust_id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
创建实体类
package com.itheima.domain;
import java.util.HashSet;
import java.util.Set;
/**
* @ClassName: Customer
* @Description:客户类
* @author jsz
* @date 2018年8月18日
*/
public class Customer {
private Long cust_id;
private String cust_name;
private String cust_source;
private String cust_industry;
private String cust_level;
private String cust_phone;
private String cust_address;
private Set<LinkMan> linkMans = new HashSet<LinkMan>();
public Customer() {
super();
// TODO Auto-generated constructor stub
}
public Customer(Long cust_id, String cust_name, String cust_source, String cust_industry, String cust_level,
String cust_phone, String cust_address, Set<LinkMan> linkMans) {
super();
this.cust_id = cust_id;
this.cust_name = cust_name;
this.cust_source = cust_source;
this.cust_industry = cust_industry;
this.cust_level = cust_level;
this.cust_phone = cust_phone;
this.cust_address = cust_address;
this.linkMans = linkMans;
}
public Long getCust_id() {
return cust_id;
}
public void setCust_id(Long cust_id) {
this.cust_id = cust_id;
}
public String getCust_name() {
return cust_name;
}
public void setCust_name(String cust_name) {
this.cust_name = cust_name;
}
public String getCust_source() {
return cust_source;
}
public void setCust_source(String cust_source) {
this.cust_source = cust_source;
}
public String getCust_industry() {
return cust_industry;
}
public void setCust_industry(String cust_industry) {
this.cust_industry = cust_industry;
}
public String getCust_level() {
return cust_level;
}
public void setCust_level(String cust_level) {
this.cust_level = cust_level;
}
public String getCust_phone() {
return cust_phone;
}
public void setCust_phone(String cust_phone) {
this.cust_phone = cust_phone;
}
public String getCust_address() {
return cust_address;
}
public void setCust_address(String cust_address) {
this.cust_address = cust_address;
}
public Set<LinkMan> getLinkMans() {
return linkMans;
}
public void setLinkMans(Set<LinkMan> linkMans) {
this.linkMans = linkMans;
}
@Override
public String toString() {
return "Customer [cust_id=" + cust_id + ", cust_name=" + cust_name + ", cust_source=" + cust_source
+ ", cust_industry=" + cust_industry + ", cust_level=" + cust_level + ", cust_phone=" + cust_phone
+ ", cust_address=" + cust_address + ", linkMans=" + linkMans + "]";
}
}
package com.itheima.domain;
/**
* @ClassName: LinkMan
* @Description:联系人类
* @author jsz
* @date 2018年8月18日
*/
public class LinkMan {
private Long lkm_id;
private String lkm_name;
private String lkm_gender;
private String lkm_phone;
private String lkm_mobile;
private String lkm_email;
private String lkm_qq;
private String lkm_position;
private String lkm_memo;
private Customer customer;
public LinkMan() {
super();
// TODO Auto-generated constructor stub
}
public LinkMan(Long lkm_id, String lkm_name, String lkm_gender, String lkm_phone, String lkm_mobile,
String lkm_email, String lkm_qq, String lkm_position, String lkm_memo, Customer customer) {
super();
this.lkm_id = lkm_id;
this.lkm_name = lkm_name;
this.lkm_gender = lkm_gender;
this.lkm_phone = lkm_phone;
this.lkm_mobile = lkm_mobile;
this.lkm_email = lkm_email;
this.lkm_qq = lkm_qq;
this.lkm_position = lkm_position;
this.lkm_memo = lkm_memo;
this.customer = customer;
}
public Long getLkm_id() {
return lkm_id;
}
public void setLkm_id(Long lkm_id) {
this.lkm_id = lkm_id;
}
public String getLkm_name() {
return lkm_name;
}
public void setLkm_name(String lkm_name) {
this.lkm_name = lkm_name;
}
public String getLkm_gender() {
return lkm_gender;
}
public void setLkm_gender(String lkm_gender) {
this.lkm_gender = lkm_gender;
}
public String getLkm_phone() {
return lkm_phone;
}
public void setLkm_phone(String lkm_phone) {
this.lkm_phone = lkm_phone;
}
public String getLkm_mobile() {
return lkm_mobile;
}
public void setLkm_mobile(String lkm_mobile) {
this.lkm_mobile = lkm_mobile;
}
public String getLkm_email() {
return lkm_email;
}
public void setLkm_email(String lkm_email) {
this.lkm_email = lkm_email;
}
public String getLkm_qq() {
return lkm_qq;
}
public void setLkm_qq(String lkm_qq) {
this.lkm_qq = lkm_qq;
}
public String getLkm_position() {
return lkm_position;
}
public void setLkm_position(String lkm_position) {
this.lkm_position = lkm_position;
}
public String getLkm_memo() {
return lkm_memo;
}
public void setLkm_memo(String lkm_memo) {
this.lkm_memo = lkm_memo;
}
public Customer getCustomer() {
return customer;
}
public void setCustomer(Customer customer) {
this.customer = customer;
}
@Override
public String toString() {
return "LinkMan [lkm_id=" + lkm_id + ", lkm_name=" + lkm_name + ", lkm_gender=" + lkm_gender + ", lkm_phone="
+ lkm_phone + ", lkm_mobile=" + lkm_mobile + ", lkm_email=" + lkm_email + ", lkm_qq=" + lkm_qq
+ ", lkm_position=" + lkm_position + ", lkm_memo=" + lkm_memo + ", customer=" + customer + "]";
}
}
映射文件
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<!-- 映射文件:创建实体类和表的映射关系 -->
<hibernate-mapping>
<class name="com.itheima.domain.Customer" table="cst_customer" catalog="crm">
<id name="cust_id" column="cust_id">
<!-- generator:主键生成策略 native:主键自动增长-->
<generator class="native" />
</id>
<property name="cust_name" column="cust_name" />
<property name="cust_source" column="cust_source" />
<property name="cust_industry" column="cust_industry" />
<property name="cust_level" column="cust_level" />
<property name="cust_address" column="cust_address" />
<property name="cust_phone" column="cust_phone" />
<!--set:配置一的一方 name:Javabean中集合的名称 inverse:放弃维护外键 lazy:延迟加载(默认:true)-->
<set name="linkMans" inverse="true">
<!-- column:表中外键 -->
<key column="lkm_cust_id"></key>
<!-- class:多的一方的类的全路径 -->
<one-to-many class="com.itheima.domain.LinkMan"/>
</set>
</class>
</hibernate-mapping>
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.itheima.domain.LinkMan" table="cst_linkman">
<id name="lkm_id" column="lkm_id">
<generator class="native" />
</id>
<property name="lkm_name" column="lkm_name" />
<property name="lkm_gender" column="lkm_gender" />
<property name="lkm_phone" column="lkm_phone" />
<property name="lkm_mobile" column="lkm_mobile" />
<property name="lkm_email" column="lkm_email" />
<property name="lkm_qq" column="lkm_qq" />
<property name="lkm_position" column="lkm_position" />
<property name="lkm_memo" column="lkm_memo" />
<!-- many-to-one:先配置多方 name:当前JavaBean中的属性 class:属性的全路径 cascade:级联操作 column:表中外键 lazy:延迟加载()-->
<many-to-one name="customer" class="com.itheima.domain.Customer"
cascade="save-update,delete" column="lkm_cust_id" />
</class>
</hibernate-mapping>
级联保存
- 保存谁,在谁的映射文件中配置cascade="save-update,delete"
- 让另外一方放弃外键维护权
package com.itheima.test;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;
import com.itheima.domain.Customer;
import com.itheima.domain.LinkMan;
import com.itheima.utils.HibernateUtils;
/**
* @ClassName: TestSave
* @Description:级联保存
* @author jsz
* @date 2018年8月20日
*/
public class TestSave {
/**
* @MethodName:test
* @Description:保存联系人,保存用户
* @throws Exception
*/
@Test
public void test() throws Exception {
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();
Customer customer = new Customer();
customer.setCust_name("张三");
LinkMan l1 = new LinkMan();
l1.setLkm_name("tom01");
LinkMan l2 = new LinkMan();
l2.setLkm_name("tom02");
// 让联系人关联客户
l1.setCustomer(customer);
l2.setCustomer(customer);
// 保存
session.save(l1);
session.save(l2);
tx.commit();
}
}
级联删除
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;
import com.itheima.domain.Customer;
import com.itheima.domain.LinkMan;
import com.itheima.utils.HibernateUtils;
public class TestDelete {
/**
* @MethodName:test01
* @Description:删除客服的时候,删除联系人
* @throws Exception
*/
@Test
public void test01() throws Exception {
Session session = HibernateUtils.getCurrentSession();
Transaction transaction = session.beginTransaction();
Customer customer = session.get(Customer.class, 5l);
session.delete(customer);
transaction.commit();
}
/**
* @MethodName:test02
* @Description:删除联系人的时候,删除客户(很少用)
* @throws Exception
*/
@Test
public void test02() throws Exception {
Session session = HibernateUtils.getCurrentSession();
Transaction transaction = session.beginTransaction();
LinkMan linkMan = session.get(LinkMan.class, 3l);
session.delete(linkMan);
transaction.commit();
}
}
冗余SQL的产生原因
hibernate一级缓存,让一方放弃外键的维护权
多对多关系映射
创建数据库
CREATE TABLE `sys_role` (
`role_id` bigint(32) NOT NULL AUTO_INCREMENT,
`role_name` varchar(32) NOT NULL COMMENT '角色名称',
`role_memo` varchar(128) DEFAULT NULL COMMENT '备注',
PRIMARY KEY (`role_id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
CREATE TABLE `sys_user` (
`user_id` bigint(32) NOT NULL AUTO_INCREMENT COMMENT '用户id',
`user_code` varchar(32) NOT NULL COMMENT '用户账号',
`user_name` varchar(64) NOT NULL COMMENT '用户名称',
`user_password` varchar(32) NOT NULL COMMENT '用户密码',
`user_state` char(1) NOT NULL COMMENT '1:正常,0:暂停',
PRIMARY KEY (`user_id`)
) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8;
CREATE TABLE `sys_user_role` (
`role_id` bigint(32) NOT NULL COMMENT '角色id',
`user_id` bigint(32) NOT NULL COMMENT '用户id',
PRIMARY KEY (`role_id`,`user_id`),
KEY `FK_user_role_user_id` (`user_id`),
CONSTRAINT `FK_user_role_role_id` FOREIGN KEY (`role_id`) REFERENCES `sys_role` (`role_id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `FK_user_role_user_id` FOREIGN KEY (`user_id`) REFERENCES `sys_user` (`user_id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
创建java类
import java.util.HashSet;
import java.util.Set;
/**
* @ClassName: User
* @Description:用户
* @author jsz
* @date 2018年8月20日
*/
public class User {
private Long user_id;// '用户id',
private String user_code;// '用户账号',
private String user_name;// '用户名称',
private String user_password;// '用户密码',
private String user_state;// '1:正常,0:暂停',
// 有角色的集合
private Set<Role> roles = new HashSet<Role>();
public User(Long user_id, String user_code, String user_name, String user_password, String user_state,
Set<Role> roles) {
super();
this.user_id = user_id;
this.user_code = user_code;
this.user_name = user_name;
this.user_password = user_password;
this.user_state = user_state;
this.roles = roles;
}
public User() {
super();
// TODO Auto-generated constructor stub
}
public Set<Role> getRoles() {
return roles;
}
public void setRoles(Set<Role> roles) {
this.roles = roles;
}
public Long getUser_id() {
return user_id;
}
public void setUser_id(Long user_id) {
this.user_id = user_id;
}
public String getUser_code() {
return user_code;
}
public void setUser_code(String user_code) {
this.user_code = user_code;
}
public String getUser_name() {
return user_name;
}
public void setUser_name(String user_name) {
this.user_name = user_name;
}
public String getUser_password() {
return user_password;
}
public void setUser_password(String user_password) {
this.user_password = user_password;
}
public String getUser_state() {
return user_state;
}
public void setUser_state(String user_state) {
this.user_state = user_state;
}
@Override
public String toString() {
return "User [user_id=" + user_id + ", user_code=" + user_code + ", user_name=" + user_name + ", user_password="
+ user_password + ", user_state=" + user_state + ", roles=" + roles + "]";
}
}
import java.util.HashSet;
import java.util.Set;
/**
* @ClassName: Role
* @Description:角色
* @author jsz
* @date 2018年8月20日
*/
public class Role {
private Long role_id;// 主键ID
private String role_name;// '角色名称',
private String role_memo;// '备注',
// 有用户的集合
private Set<User> users = new HashSet<User>();
public Role(Long role_id, String role_name, String role_memo, Set<User> users) {
super();
this.role_id = role_id;
this.role_name = role_name;
this.role_memo = role_memo;
this.users = users;
}
public Role() {
super();
// TODO Auto-generated constructor stub
}
public Set<User> getUsers() {
return users;
}
public void setUsers(Set<User> users) {
this.users = users;
}
public Long getRole_id() {
return role_id;
}
public void setRole_id(Long role_id) {
this.role_id = role_id;
}
public String getRole_name() {
return role_name;
}
public void setRole_name(String role_name) {
this.role_name = role_name;
}
public String getRole_memo() {
return role_memo;
}
public void setRole_memo(String role_memo) {
this.role_memo = role_memo;
}
@Override
public String toString() {
return "Role [role_id=" + role_id + ", role_name=" + role_name + ", role_memo=" + role_memo + ", users=" + users
+ "]";
}
}
配置映射文件
<set name="当前Javabean中的集合名称" table="中间表的名称">
<key column="当前Javabean在中间表的外键"/>
<many-to-many class="集合中对象的全路径" column="集合中的对象在中间表的外键"/>
</set>
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.itheima.domain.User" table="sys_user" catalog="crm">
<id name="user_id" column="user_id">
<generator class="native" />
</id>
<property name="user_code" column="user_code" />
<property name="user_name" column="user_name" />
<property name="user_password" column="user_password" />
<property name="user_state" column="user_state" />
<!-- 配置多对多 name:当前java类中的集合 table:中间表 -->
<set name="roles" table="sys_user_role" cascade="save-update">
<!-- column:当前java类在中间表的外键-->
<key column="user_id" />
<!-- class:集合中对象的全路径 column:集合中对象在中间表的外键的名称 -->
<many-to-many class="com.itheima.domain.Role" column="role_id" />
</set>
</class>
</hibernate-mapping>
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.itheima.domain.Role" table="sys_role" catalog="crm">
<id name="role_id" column="role_id">
<generator class="native" />
</id>
<property name="role_name" column="role_name" />
<property name="role_memo" column="role_memo"></property>
<!-- 配置多对多 name:当前java类中的集合 table:中间表 -->
<set name="users" table="sys_user_role" cascade="save-update" inverse="true">
<!-- column:当前java类在中间表的外键-->
<key column="role_id" />
<!-- class:集合中对象的全路径 column:集合中对象在中间表的外键的名称 -->
<many-to-many class="com.itheima.domain.User" column="user_id" />
</set>
</class>
</hibernate-mapping>
级联保存
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;
import com.itheima.domain.Role;
import com.itheima.domain.User;
import com.itheima.utils.HibernateUtils;
public class Demo02 {
/**
* @MethodName:test01
* @Description:双向关联
* @throws Exception
*/
@Test
public void test01() throws Exception {
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();
User u1 = new User();
u1.setUser_name("张三");
User u2 = new User();
u2.setUser_name("李四");
Role r1 = new Role();
r1.setRole_name("经理");
Role r2 = new Role();
r2.setRole_name("演员");
// 双向关联
u1.getRoles().add(r1);
u1.getRoles().add(r2);
r1.getUsers().add(u1);
r2.getUsers().add(u1);
u2.getRoles().add(r1);
r1.getUsers().add(u2);
session.save(u1);
session.save(u2);
session.save(r1);
session.save(r2);
tx.commit();
}
/**
* @MethodName:test02
* @Description:级联保存:保存用户,保存关联的角色
* @throws Exception
*/
@Test
public void test02() throws Exception {
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();
User u1 = new User();
u1.setUser_name("张三");
User u2 = new User();
u2.setUser_name("李四");
Role r1 = new Role();
r1.setRole_name("经理");
Role r2 = new Role();
r2.setRole_name("演员");
// 单项关联
u1.getRoles().add(r1);
u1.getRoles().add(r2);
u2.getRoles().add(r1);
session.save(u1);
session.save(u2);
tx.commit();
}
}
级联删除
import static org.junit.Assert.*;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;
import com.itheima.domain.Role;
import com.itheima.domain.User;
import com.itheima.utils.HibernateUtils;
public class Demo02 {
/**
* @MethodName:test01
* @Description:双向关联
* @throws Exception
*/
@Test
public void test01() throws Exception {
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();
User u1 = new User();
u1.setUser_name("张三");
User u2 = new User();
u2.setUser_name("李四");
Role r1 = new Role();
r1.setRole_name("经理");
Role r2 = new Role();
r2.setRole_name("演员");
// 双向关联
u1.getRoles().add(r1);
u1.getRoles().add(r2);
r1.getUsers().add(u1);
r2.getUsers().add(u1);
u2.getRoles().add(r1);
r1.getUsers().add(u2);
session.save(u1);
session.save(u2);
session.save(r1);
session.save(r2);
tx.commit();
}
/**
* @MethodName:test02
* @Description:级联保存:保存用户,保存关联的角色
* @throws Exception
*/
@Test
public void test02() throws Exception {
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();
User u1 = new User();
u1.setUser_name("张三");
User u2 = new User();
u2.setUser_name("李四");
Role r1 = new Role();
r1.setRole_name("经理");
Role r2 = new Role();
r2.setRole_name("演员");
// 单项关联
u1.getRoles().add(r1);
u1.getRoles().add(r2);
u2.getRoles().add(r1);
session.save(u1);
session.save(u2);
tx.commit();
}
/**
* @MethodName:test03
* @Description:级联删除,实际开发中不用,全部删除
* @throws Exception
*/
@Test
public void test03() throws Exception {
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();
User user = session.get(User.class, 1l);
session.delete(user);
tx.commit();
}
/**
* @MethodName:test04
* @Description:删除张三的演员角色
* @throws Exception
*/
@Test
public void test04() throws Exception {
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();
User u1 = session.get(User.class, 1l);
Role r2 = session.get(Role.class, 2l);
u1.getRoles().remove(r2);
tx.commit();
}
}
配置级联的原则
操作谁比较多,在XML文件中配置级联:cascade="save-update"
让另一方放弃外键维护权:inverse="true"