my demo hbm:


<class name="Customer" table="Customer" lazy="true">
<id name="customereID" type="int" ....>
<generator class="native" />
</id>
<property name="name" type="string" ..../>

<list name="phoneNumbers" lazy="true" table="CusPhone">
<key column="CustomerID"/>
<list-index column="PhoneIndex"/>
<element type="string" column="PhoneNumber" not-null="true"/>
</list>
</class>

this hbm don't set "cascade" property, so it's "none"

.......
Customer tom = new Customer();
tom.addPhone("1");
tom.addPhone("2");
.....
session.merge(tom);
......

I think this just save tom in Customer table(without CusPhone table),
but CusPhone also saved actually.

is anyone can explain this?

The cascade attribute determines whether or not changes to associated objects are flushed when a base object is changed/flushed. There are no associated objects in your mapping: elements are values, not entities. The list isn't inverse="true", so it is part of Customer: it is not an associated object, so cascade doesn't apply to it. In fact, because this is a list of values (not entities), it can't be declared inverse="true" (or at least, it can't usefully be declared inverse="true").

If the list contained entities instead of elements, then changing a value in one of the entities would not cause the relevant DB row to be updated when the parent entity is flushed. That is what the cascade="none" does. So if you want the phone numbers to not cascade, you'll have to model the CusPhone table as a separate class, instead of using element.