# 7.5.1\. 一对多（one to many） /多对一（ many to one） _基于连接表的双向一对多关联_。注意`inverse="true"`可以出现在关联的任意一端，即collection端或者join端。 ``` <class name="Person"> <id name="id" column="personId"> <generator class="native"/> </id> <set name="addresses" table="PersonAddress"> <key column="personId"/> <many-to-many column="addressId" unique="true" class="Address"/> </set> </class> <class name="Address"> <id name="id" column="addressId"> <generator class="native"/> </id> <join table="PersonAddress" inverse="true" optional="true"> <key column="addressId"/> <many-to-one name="person" column="personId" not-null="true"/> </join> </class> ``` ``` create table Person ( personId bigint not null primary key ) create table PersonAddress ( personId bigint not null, addressId bigint not null primary key ) create table Address ( addressId bigint not null primary key ) ```