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POwhat does the Set type in a Entry
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  1. POwhat does the Set type in a Entry
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    copied!<p>I have two tables in db,and one owns a foreign key from another,the fllowing is the schema:</p> <p>//table featureInfo</p> <pre><code>SET FOREIGN_KEY_CHECKS=0; -- ---------------------------- -- Table structure for featureinfo -- ---------------------------- DROP TABLE IF EXISTS `featureinfo`; CREATE TABLE `featureinfo` ( `Id` int(11) NOT NULL AUTO_INCREMENT, `globalId` int(11) NOT NULL DEFAULT '0', `name` varchar(255) NOT NULL DEFAULT '', PRIMARY KEY (`Id`), KEY `globalId` (`globalId`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; </code></pre> <p>//another table featurefix</p> <pre><code>SET FOREIGN_KEY_CHECKS=0; -- ---------------------------- -- Table structure for featurefix -- ---------------------------- DROP TABLE IF EXISTS `featurefix`; CREATE TABLE `featurefix` ( `Id` int(11) NOT NULL AUTO_INCREMENT, `globalId` int(11) NOT NULL DEFAULT '0', `modifyname` varchar(255) NOT NULL DEFAULT '', PRIMARY KEY (`Id`), KEY `FK-Guid` (`globalId`), CONSTRAINT `FK-Guid` FOREIGN KEY (`globalId`) REFERENCES `featureinfo` (`globalId`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; </code></pre> <p>Then I use the hbm2java to create the entry class:</p> <pre><code>public class Featureinfo implements java.io.Serializable { private Integer id; private int globalId; private String name; private Set featurefixes = new HashSet(0); public Featureinfo() {} } </code></pre> <p>Now I wonder why there is a set attribute in FeatureInfo?</p> <p>And the Featureinfo.hbm.xml:</p> <pre><code>&lt;hibernate-mapping&gt; &lt;class name="com.pojo.Featureinfo" table="featureinfo" catalog="hibernateset"&gt; &lt;id name="id" type="java.lang.Integer"&gt; &lt;column name="Id" /&gt; &lt;generator class="identity" /&gt; &lt;/id&gt; &lt;property name="globalId" type="int"&gt; &lt;column name="globalId" not-null="true" /&gt; &lt;/property&gt; &lt;property name="name" type="string"&gt; &lt;column name="name" not-null="true" /&gt; &lt;/property&gt; &lt;set name="featurefixes" inverse="true"&gt; &lt;key&gt; &lt;column name="globalId" not-null="true" /&gt; &lt;/key&gt; &lt;one-to-many class="com.pojo.Featurefix" /&gt; &lt;/set&gt; &lt;/class&gt; &lt;/hibernate-mapping&gt; </code></pre> <p>The set element are defines, why not use the "joined-subclass" instead?</p> <p>Also what is the difference between the "set/map/list/idbag" and "one-to-many/many-to-one" in the mapping xml file ?</p>
 

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