department与employee是一对多关系。
set
<set name="emps" inverse="true"> <key column="depart_id"/> <one-to-many class="Employee" /> </set>
list，关键在于有一定顺序：
<list name="emps"> <key column="depart_id" /> <list-index column="order_col" /> <one-to-many class="Employee" /> </list>
所以需要配置<list-index column="order_col" />
map： Map<Strig,Employee> emps;
<map name="emps"> <key column="depart_id" /> <map-key type="string" column="name"/> <one-to-many class="Employee" /> </map>
bag:想用list又不需要保证顺序
<bag name="emps"> <key column="depart_id" /> <one-to-many class="Employee" /> </bag>
原文：http://www.cnblogs.com/rixiang/p/5172951.html