Problem with duplicates

kangooruuu · **Posted:** Thu Mar 19, 2009 1:41 pm

Hi, I've mapped a table this way:

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="pt.global.data.hibernate.models" default-access="field">
    <class name="GraEvent" table="GRA_EVENT">
      <id name="id" column="ID_SEQ">
            <generator class="increment"/>
        </id>
        <natural-id mutable="false">
         <property name="idCalendar" update="false">
            <column name="ID_CALENDAR" 
               unique="true" 
               length="30" 
               not-null="true" />
         </property>
      </natural-id>
        <property column="TITLE" not-null="true" name="title" length="100" />
        <property column="TYPE" not-null="true" name="type" length="5" />
        <property column="STATUS" not-null="true" name="status" length="5" />
    </class>
    
</hibernate-mapping>

But it is allowing me to insert records with the same ID_CALENDAR. Shouldn't the framework throw an exception when I tried to insert a duplicate?

Kind regards,

Carlos Ferreira

nordborg · **Posted:** Thu Mar 19, 2009 2:56 pm

It is really not possible to do this inside the framework considering that multiple transactions may be going on at once. Instead, the check is assumed to be made by the database. If you use the schema generation tool to create the database, Hibernate will also create the proper constraints for checking the uniqueness. In your case, you'll need a unique constraint on the ID_CALENDAR column.