hibernate筆記（三）------many2many

create table e_order ( orderid integer not null auto_increment, name varchar(255), cost double precision, paywayid integer, userid integer, statusid integer, primary key (orderid) ) create table e_orderLine ( orderlineid integer not null auto_increment, orderid integer, amount integer, productid integer, primary key (orderlineid) ) 聯合主鍵 create table e_order_orderline ( orderid integer not null, orderlineid integer not null, primary key (orderlineid, orderid) ) hibernate多對多關聯映射(單向Order---->OrderLine)

 

多對多單向跟一對多單向很相似。只是中間插入了一個表別對應兩邊表的id值

 

<class name="Order" table="e_order"> <id name="orderid"> <generator class="native" /> </id> <property name="name" /> <property name="cost" /> <set name="orders" table="e_order_orderline" order-by="orderlineid"> <key column="orderid"/> <many-to-many class="OrderLine" column="orderlineid"></many-to-many> </set> <many-to-one name="payway" column="paywayid"/> <many-to-one name="user" column="userid"/> <many-to-one name="status" column="statusid"/> </class>

 

 

hibernate多對多關聯映射(單向Order<---->OrderLine)

table屬性值必須和單向關聯中的table屬性值一致
<key>中column屬性值要與單向關聯中的<many-to-many>標籤中的column屬性值一致
在<many-to-many>中的column屬性值要與單向關聯中<key>標籤的column屬性值一致

 

 

這就需要在OrderLine中再加入一個set  對應  Orders

 

<class name="OrderLine" table="e_orderLine"> <id name="orderlineid"> <generator class="native" /> </id> <property name="orderid" /> <property name="amount" /> <set name="orders" table="e_order_orderline"> <key column="orderlineid"/> <many-to-many class="OrderLine" column="orderid"/> </set> <many-to-one name="product" column="productid"/> </class>