一对多

场景模拟:用户(一)对订单(多)

1.建表

　　创建客户表，字段有：客户id，客户姓名，客户性别，客户年龄，客户年纪，客户电话。

　　创建订单表，字段有：订单编号，明细编号，客户编号(外键)

DROP TABLE IF EXISTS ordersA;DROP TABLE IF EXISTS customerA; CREATE TABLE customerA(    cust_id        TINYINT  PRIMARY KEY AUTO_INCREMENT,    cust_name　　 　VARCHAR(30),    cust_gender 　　CHAR(5),    cust_age       SMALLINT,    cust_phone     VARCHAR(20));CREATE TABLE ordersA(    order_id VARCHAR(50) PRIMARY KEY,    detail_id   VARCHAR(50),    cust_order_id TINYINT,    CONSTRAINT fk_customerA_ordersA FOREIGN KEY(cust_order_id) REFERENCES customerA(cust_id) ON DELETE CASCADE);

2.创建项目，配置hibernate.cfg.xml主配置文件

             
         
                          
       
        com.mysql.jdbc.Driver
               
       
        jdbc:mysql:///test
               
       
        root
               
       
        123456
                       
       
        true
               
       
        true
               
       
        update
               
       
        org.hibernate.dialect.MySQLDialect
                       
               
       
        thread
                   
      
     

3.创建实体

　　创建用户实体类:基本属性+配置一对多的属性(set集合存储多个订单)

　   创建订单实体类:基本属性+配置多对一的属性(Customer类存储客户实体)

package deep.domain;import java.io.Serializable;import java.util.HashSet;import java.util.Set;/** * 客户实体类 * @author DeepSleeping * */public class Customer implements Serializable {    private static final long serialVersionUID = 1L;    private Integer cust_id;    private String cust_name;    private String cust_gender;    private Integer cust_age;    private String cust_phone;        /*     * 一对多     * */    private Set
     
       ods = new HashSet
      
       ();    public Integer getCust_id() {        return cust_id;    }    public void setCust_id(Integer 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_gender() {        return cust_gender;    }    public void setCust_gender(String cust_gender) {        this.cust_gender = cust_gender;    }    public Integer getCust_age() {        return cust_age;    }    public void setCust_age(Integer cust_age) {        this.cust_age = cust_age;    }    public String getCust_phone() {        return cust_phone;    }    public void setCust_phone(String cust_phone) {        this.cust_phone = cust_phone;    }    public Set
       
         getOds() {        return ods;    }    public void setOds(Set
        
          ods) {        this.ods = ods;    }}
        
       
      
     

package deep.domain;import java.io.Serializable;/** * 订单实体类 * @author DeepSleeping * */public class Order implements Serializable{    private static final long serialVersionUID = 1L;    private String order_id;    private String detail_id;            /*     * 多对一     */    private Customer cst;        public String getOrder_id() {        return order_id;    }    public void setOrder_id(String order_id) {        this.order_id = order_id;    }    public String getDetail_id() {        return detail_id;    }    public void setDetail_id(String detail_id) {        this.detail_id = detail_id;    }    public Customer getCst() {        return cst;    }    public void setCst(Customer cst) {        this.cst = cst;    }                }

4.配置实体的映射文件:Customer.hbm.xml,Order.hbm.xml

　　Customer.hbm.xml中的set标签对中：

　　set：存储多的一方的集合 name:存储多的一方的集合属性名

　　key标签对:配置外键

　　column:是数据库中外键的字段名(注意这里写的名一定要与后面多方中配置外键的名称一致，否则就会创建多个外键)

      <one-to-many> 是表示，我这里是一对多，对的多的一方的实体类的路径是:class = "order"(这里只写order是因为在配置文件中我已经用package定位到实体类的包下了)

5.在主配置文件中引入两个实体对应的映射文件

6.添加订单到客户id为1的客户中

package deep.test;import java.util.UUID;import org.hibernate.Session;import org.junit.Test;import deep.common.HibernateUtils;import deep.domain.Customer;import deep.domain.Order;public class TestClass {    /**     * 添加订单到客户     */    @Test    public void fun(){                Session session = HibernateUtils.getSession();        session.getTransaction().begin();                        try {            //获取客户 持久            Customer cst = session.get(Customer.class, 1);            //新建订单 瞬时            Order od = new Order();            od.setOrder_id(UUID.randomUUID().toString());            od.setDetail_id(UUID.randomUUID().toString());            //表达客户和订单的关系            cst.getOds().add(od);            //表达订单和客户的关系            od.setCst(cst);            //持久化订单            session.save(od);        } catch (Exception e) {            session.getTransaction().rollback();            e.printStackTrace();        }                session.getTransaction().commit();    }}

 

 

添加订单成功！