inverse="true"
?<set
??????? name="orders"
??????? inverse="true"
??????? cascade="save-update"
??????? >
???????
??????? <key column="customer_id" not-null="true"/>
??????? <one-to-many />
???? </set>?
?
当 设置?? inverse="true" 是 不会像外键 customer_id 插入值，即使设置了 not-null = "true"
