Hibernate,级联保存为什么无效？？
有两个表分别是Customers和Orders，它们是一对多的关系，它们的*.hbm.xml文件分别是
Customer.hbm.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping package="org.pojo">
<class name="Customer" table="CUSTOMERS" dynamic-insert="true" dynamic-update="true" >
<id name ="id" column ="ID" type="integer">
<generator class="sequence">
<param name="sequence">seq_id</param>
</generator>
</id>

<property name="name" column="NAME" type="string" not-null="true"></property>
<property name="sex" access="field"></property>

<set name="orders"
inverse="true"
cascade="save-update">
<key column="CUSTOMER_ID"></key>
<one-to-many class="org.pojo.Order"/>
</set>

<property name="totalPrice" formula=" (select sum(o.price) from ORDERS o where o.CUSTOMER_ID=ID)"/>
<property name="description" column="DESCRIPTION" type="text"></property>
</class>
</hibernate-mapping>

Order.hbm.xml文件为
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping package="org.pojo">
<class name="Order" dynamic-insert="true" dynamic-update="true" >
<id name ="id" column ="ID" type="integer">
<generator class="sequence" >
<param name="sequence">seq_order_id</param>
</generator>
</id>

<property name="orderNumber" column="ORDER_NUMBER" type="string" ></property>
<property name="price"></property>

<many-to-one name="customer" class="org.pojo.Customer" >
<column name="CUSTOMER_ID"></column>
</many-to-one>
</class>

</hibernate-mapping>
因为我在Customer.hbm.xml的<set>中设置了cascade="save-update"，理论上在新增Customer时应该级联保存Order的，
但发现Customer能保存，Order无法保存。程序也没报错。我看到控制台上对于Customers表是打印了insert语句，
但对于Orders表，打印的是update语句。为什么不是insert语句？为什么级联无法保存Order?

Customer customer = new Customer("LiShi","Lin",'M',new HashSet(),null);
Order order1 = new Order("Order0001",100.0,customer );
customer_1.getOrders().add(order1);
saveCustomer_1(customer);

在持久类的Customer也设置有Order的setter/getter了。

[解决办法]
<set name="orders"
inverse="true"
cascade="save-update">
<key column="CUSTOMER_ID"> </key>

<one-to-many class="org.pojo.Order"/>
</set>
把inverse去掉试试
[解决办法]

Java code

Employee e=new Employee();Reward r=new Reward();r.setEmployee(e);session.save(r);
[解决办法]
你设置了inverse="true"就是所谓的控制反转， 这样子一来时方便在多的一端（Order）保存时顺便保存了（Customers） 一的一端  
再多的一端保存时  
  Customer customer = new Customer("LiShi","Lin",'M',new HashSet(),null);  
Order order1 = new Order("Order0001",100.0,customer );  
order1.setCustomer(Customer);  
saveOrder(order1 );  
  这样两条同时保存 这就是设置 inverse="true"的好处

现在你将控制放在了多的一端（Order） 那么在一的一端你需要下面这样才行

Customer customer = new Customer("LiShi","Lin",'M',new HashSet(),null);  
Order order1 = new Order("Order0001",100.0,customer );  
order1.setCustomer(customer );
customer_1.getOrders().add(order1);  
saveCustomer_1(customer);  

这时候就能正常级联保存  
在有问题的话 就到电驴里面下载一下 尚学堂 j2ee 视频教程，里面有详细的解释