I have a bi-directional association between Item class and Bid class. (based upon An Item can contain many Bids)

<!--Mappings are as follows -->

<class name="com.hibernateproject.domain.Item" table="ITEM">
<id name="iid" type="int" unsaved-value="null">
<generator class="increment"/>
</id>
<property name="itemName" type="string"/>
<list name="bids" inverse="true" cascade="all" table="BID">
<key column="item_bid"/>
<index column="index_column"/>
<one-to-many class="com.hibernateproject.domain.Bid" />
</list>
</class>

<class name="com.hibernateproject.domain.Bid" table="BID">
<id name="bid" type="int" unsaved-value="null">
<generator class="increment"/>
</id>
<property name="bidValue" type="long" />
<many-to-one name="item" column="item_bid" class="com.hibernateproject.domain.Item"
not-null="true"/>
</class>

<!--Tables are as follows:-->

create table item(iid number, itemName varchar(20));
create table bid(bid number, bidValue long, item_bid number, index_column number);

<!--Main Class for Saving Item cascading Bid -->
session.beginTransaction();

Item item = new Item();
item.setItemName("Item2");
item.setBids(new ArrayList());
Bid bid = new Bid(2000);
bid.setItem(item);
item.getBids().add(bid);
session.save(item);

session.getTransaction().commit();

My mapping files are in the classpath. It is not cascading Bid class. Instead, it is executing SQL as follows:
Hibernate: select max(iid) from ITEM
Hibernate: insert into ITEM (itemName, iid) values (?, ?)
Hibernate: update BID set bidValue=?, item_bid=? where bid=?

Please suggest.