hibernate hbm.xml配置文件说明

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<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>

   <class name="com.oreilly.hh.Track" table="TRACK">
     <meta attribute="class-description">
        Represents a single playable track in the music database.
        @author Jim Elliot(with help from Hibernate)
     </meta>

     <id name="id" type="int" column="TRACK_ID">
       <meta attribute="scope-set">protected</meta>
          <generator class="native"/>
     </id>

     <property name="title" type="string" not-null="true"/>

     <property name="filePath" type="string" not-null="true"/>

     <property name="playTime" type="time">
        <meta attribute="field-description">Playing time</meta>
     </property>

     <property name="added" type="date">
        <meta attribute="field-description">When the track was created</meta>
     </property>

     <property name="volume" type="short" not-null="true">
        <meta attribute="field-description">How loud to play the track</meta>
     </property>

   </class>
</hibernate-mapping>
     说明如下：

1.<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//hibernate/Hibernate Mapping DTD 2.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>

用于导言说明，说明它的文件格式定义。

2.<hibernate-mapping>标签里是真正的映射。

3.<class name="com.oreilly.hh.Track" table="TRACK">
定义一个类com.oreilly.hh.Track的映射。（可以定义任意多个类在一个映射文件里）。表示存在数据库表TRACK中。

4. <meta attribute="class-description">
        Represents a single playable track in the music database.
        @author Jim Elliot(with help from Hibernate)
     </meta>
定义了说明，可以被JavaDoc读取。

5. <id name="id" type="int" column="TRACK_ID">
       <meta attribute="scope-set">protected</meta>
          <generator class="native"/>
     </id>
定义了类属性和数据库表列的映射。   <generator class="native"/>是表示ID生成策略，此种策略有多种。

6. <property name="volume" type="short" not-null="true">
<meta attribute="field-description">How loud to play the track</meta>
</property> 定义了说明，可以被JavaDoc读取。