id
category_id

id
name

class Category extends Table
{
    private Set articles = new HashSet();
   
    [...]
   
    public Set getArticles() {
        return articles;
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="de.flabben.table.Category" schema="flabben" table="category">
        <id name="id" column="category_id" type="java.lang.Integer">
            <generator class="sequence">
                <param name="sequence">flabben.category_id_seq</param>
            </generator>
        </id>
        <property name="name" column="category_name" not-null="true" type="java.lang.String" />
        <set name="articles" schema="flabben" table="article">
            <key not-null="true" column="category_id" />
            <one-to-many class="de.flabben.table.Article" />
        </set>
    </class>
</hibernate-mapping>

init:
deps-jar:
compile:
run:
16:25:44,137  INFO Environment:514 - Hibernate 3.2.5
16:25:44,153  INFO Environment:532 - loaded properties from resource hibernate.properties: {<hibernate-configuration>=, <session-factory>=, <mapping=resource="de/flabben/table/definition/tag.hbm.xml" />, "-//Hibernate/Hibernate=Configuration DTD 3.0//EN", </session-factory>=, <?xml=version="1.0" encoding="utf-8"?>, hibernate.bytecode.use_reflection_optimizer=false, </hibernate-configuration>=, <!--=mapping files -->, "http=//hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">, <!DOCTYPE=hibernate-configuration PUBLIC, <property=name="hibernate.show_sql">true</property>}
16:25:44,160  INFO Environment:681 - Bytecode provider name : cglib
16:25:44,164  INFO Environment:598 - using JDK 1.4 java.sql.Timestamp handling
16:25:44,280  INFO Configuration:1426 - configuring from resource: /hibernate.cfg.xml
16:25:44,282  INFO Configuration:1403 - Configuration resource: /hibernate.cfg.xml
16:25:44,732  INFO Configuration:553 - Reading mappings from resource : de/flabben/table/definition/article.hbm.xml
16:25:44,864  INFO HbmBinder:300 - Mapping class: de.flabben.table.Article -> article
16:25:44,881  INFO HbmBinder:1422 - Mapping collection: de.flabben.table.Article.tags -> article_tag
16:25:44,886  INFO Configuration:553 - Reading mappings from resource : de/flabben/table/definition/article_tag.hbm.xml
16:25:44,927  INFO HbmBinder:300 - Mapping class: de.flabben.table.ArticleTag -> article_tag
16:25:44,930  INFO Configuration:553 - Reading mappings from resource : de/flabben/table/definition/author.hbm.xml
16:25:44,988  INFO HbmBinder:300 - Mapping class: de.flabben.table.Author -> author
16:25:44,991  INFO Configuration:553 - Reading mappings from resource : de/flabben/table/definition/category.hbm.xml
16:25:45,011  INFO HbmBinder:300 - Mapping class: de.flabben.table.Category -> category
16:25:45,013  INFO Configuration:553 - Reading mappings from resource : de/flabben/table/definition/comment.hbm.xml
16:25:45,042  INFO HbmBinder:300 - Mapping class: de.flabben.table.Comment -> comment
16:25:45,045  INFO Configuration:553 - Reading mappings from resource : de/flabben/table/definition/tag.hbm.xml
16:25:45,058  INFO HbmBinder:300 - Mapping class: de.flabben.table.Tag -> tag
16:25:45,059  INFO Configuration:1541 - Configured SessionFactory: null
16:25:45,063 DEBUG InitSessionFactory:118 - classic factory
16:25:45,119  INFO HbmBinder:2385 - Mapping collection: de.flabben.table.Category.articles -> article
%%%% Error Creating HibernateSessionFactory %%%%
org.hibernate.MappingException: Repeated column in mapping for entity: de.flabben.table.Article column: category_id (should be mapped with insert="false" update="false")
        at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:652)
        at org.hibernate.mapping.PersistentClass.checkPropertyColumnDuplication(PersistentClass.java:674)
        at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:696)
        at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:450)
        at org.hibernate.mapping.RootClass.validate(RootClass.java:192)
        at org.hibernate.cfg.Configuration.validate(Configuration.java:1102)
        at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1287)
        at de.flabben.hibernate.InitSessionFactory.initSessionFactory(InitSessionFactory.java:119)
        at de.flabben.hibernate.InitSessionFactory.getInstance(InitSessionFactory.java:60)
        at de.flabben.application.Main.main(Main.java:29)
Exception in thread "main" org.hibernate.HibernateException: Could not initialize the Hibernate configuration
        at de.flabben.hibernate.InitSessionFactory.initSessionFactory(InitSessionFactory.java:127)
        at de.flabben.hibernate.InitSessionFactory.getInstance(InitSessionFactory.java:60)
        at de.flabben.application.Main.main(Main.java:29)
Java Result: 1
BUILD SUCCESSFUL (total time: 1 second)