hibernate--a one-to-many/many pair

One-to-many associations (multi-pair):

    One-to-many association mappings:        Add a foreign key to one end of a multi-point, and it maintains a relationship that points    to many-to-one correlation mappings: one end of a        foreign key points to one end, it maintains the relationship is more point to a
Add in config file:   use <set><key></key><one-to-many></one-to-many></set> on one end       <key> The foreign key field specified must be the same as the <many-to-one> specified foreign key field  at the multi-end use <many-to-one>

Relationship between the Customer table and the order table in the database:

To create an entity class:

 public  class   Customer { private   Integer ID;     private   String name;     private   Character gender;     private   Integer age;     private   String level;         //one-to-many private set<order> orders = new hashset<order> ();  public   Customer () { super   (); } 
 
 getters and setters}  

 Public class Order {    private  Integer ID;     Private String OrderNo;     Private String productName;         //Many to a    private customer customer    ;  Public Order () {        Super();         // TODO auto-generated Constructor stub     }

　　getters and Setters}

To create a mapping file:

 class  name= " Com.roxy.hibernate.pojo.Customer "table=" T_customer "> <id name=" id "column=" c_id "> <gene Rator class  = "native" ></generator> </id> <prope Rty name= "name" column= "C_name" Not-null  = "true" ></property> <prope Rty name= "Gender" column= "C_gender" length= "1" ></property> <property name= "age" column= "C_age" ></  property> <property name= "level" column= "C_level" length= "></property>  <set name=" Orders "> <key column=" customer_id "></key> <one-to- Many class= "Com.roxy.hibernate.pojo.Order"/> </set>  </class>

package = "Com.roxy.hibernate.pojo" >    < Mapping!--classes and tables-    <class name= "Order" table = "T_order" >        <id name= "id" column= "id" >            class= "Native" ></generator>        </ Id>        <!--other properties map--        <property name= "OrderNo" column= "OrderNo" length= "></property>"        <property name= "ProductName" column= "Product_Name" length= "></property>        <!-- Many-to-one and        <many-to-one name= "Customer" class= "Customer" column= "customer_id"        /> </ Class>
To create a configuration file:
        <!--mapping file--        <mapping resource= "Com/roxy/hibernate/pojo/customer.hbm.xml"/>        <mapping Resource= "Com/roxy/hibernate/pojo/order.hbm.xml"/>
To view and parse the SQL statement:
hibernate:alter table t_order Add constraint fkesy3n2gc3fa0s3trrk3tvyv9a foreign key (Customer_i d) References T_customer (c_id)

-----Hibernate first add a foreign key association for T_order and T_customer
Hibernate:insert into T_customer (C_name, C_gender, C_age, C_level) VALUES (?, ?, ?, ?)

----- inserting data into the T_customer (Session.save (Cust);)
Hibernate:insert into T_order (OrderNo, product_name, customer_id) VALUES (?, ?, ?)

----- inserting data into the T_order (Session.save (O1);)
Hibernate:insert into T_order (OrderNo, product_name, customer_id) VALUES (?, ?, ?)
Inserting data into the T_order (Session.save (O2);)
Hibernate:     update        t_order     set        customer_id=?      where        id=?
----- maintains a relationship between two tables, hibernate updates T_customer data
Hibernate:     update        t_order     set        customer_id=?      where        id=?
-----Maintain the relationship between two tables, hibernate updates the T_customer data
hibernate--a one-to-many/many pair