# 7.2.1\. 多对一(many to one) _单向many-to-one关联_是最常见的单向关联关系。 ``` <class name="Person"> <id name="id" column="personId"> <generator class="native"/> </id> <many-to-one name="address" column="addressId" not-null="true"/> </class> <class name="Address"> <id name="id" column="addressId"> <generator class="native"/> </id> </class> ``` ``` create table Person ( personId bigint not null primary key, addressId bigint not null ) create table Address ( addressId bigint not null primary key ) ```