hibernae 一对一例子

CREATE TABLE `author` (
      `id` int(11) NOT NULL auto_increment,
      `name` varchar(50) default NULL,
      PRIMARY KEY  (`id`)
    );
    
    
 CREATE TABLE `topic` (
      `id` int(11) NOT NULL auto_increment,
      `name` varchar(50) default NULL,
      `user_id` int(11) default NULL,
      PRIMARY KEY  (`id`)
    );

<many-to-one 
        	name="author" 
        	class="kk.Author" 
        	fetch="select"
        	unique="true"
        	cascade="save-update"
        	not-null="true">
            <column name="user_id" />
</many-to-one>

<one-to-one 
        	name="topic"
        	class="kk.Topic"	
        	property-ref="author"
        	cascade="save-update"
        	>
        </one-to-one>