Hibernate一对多的问题,请教高手,解答必给分

Question

兄弟看下这个吧，你在处理一对多的时候,没必要多设一次的，只有在多对一的时候设置，
http://www.javaworld.com.tw/confluence/pages/viewpage.action?pageId=1775最好看看这个页啦，把问题调出来后给大家说下啦，让大家少花时间去调啦！！

Answer 1

看看以下的示例可能对你有所帮助
create table student
(sid varchar(32) not null primary key,
 sname varchar(16),
 sage varchar(16),
)create table book
(bid varchar(32) not null primary key,
bname varchar(16),
bprice varchar(16),
sid varchar(32)
)
Student.hbm.xml的内容如下
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping
    PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd"><hibernate-mapping>    <class name="com.test.Student" table="student" >        <id name="sid" type="string" unsaved-value="null" >
            <column name="sid" sql-type="char(32)" not-null="true"/>
<generator class="uuid.hex"/>
</id>        <property name="sname">
            <column name="sname" sql-type="varchar(16)" not-null="true"/>
        </property>        <property name="sage">
    <column name="sage" sql-type="varchar(16)" not-null="true"/>
        </property> <set name="book" cascade="all" outer-join="true">
    <key column="sid"/>
            <one-to-many class="com.test.Book" />
        </set>    </class></hibernate-mapping>Book.hbm.xml
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping
    PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd"><hibernate-mapping>    <class name="com.test.Book" table="book" >        <id name="bid" type="string" unsaved-value="null" >
            <column name="bid" sql-type="char(32)" not-null="true"/>
            <generator class="uuid.hex"/>
        </id>        <property name="bname">
            <column name="bname" sql-type="varchar(16)" not-null="true"/>
        </property>        <property name="bprice">
    <column name="bprice" sql-type="varchar(16)" not-null="true"/>
        </property>    </class></hibernate-mapping>

Answer 2

dog.setMyRoom(room);
 session.save(dog);