Hibernate 多对一 外键问题

[yang1707]

hibernate单向多对一，可以不生成外键吗？

[it491328322]

可以只配置单向的多对一的。。。

[yang1707]

关键不在单向多对一,而在反向生成表时,不生成外键

[wilburwei]

User表：uid,uname,did
Dept表：did,pname

pid外键
1.可以在User端配多对一

   public class User{
       private int uid;
       private String uname;
       private Dept dept;

      ..............

   }

   public class Dept {
	private int did;
	private String dname;

      ..   ..... 
   }


   <hibernate-mapping>
	<class name=".......User" table="..user..">
		<id name="uid" column="uid" type="int">
			<generator class="assigned"/>
		</id>

		<property name="uname" column="uname" type="java.lang.String"/>

		<many-to-one name="dept" class=".........Dept" column="pid" unique="true"/>
		
	</class>
</hibernate-mapping> 

<hibernate-mapping>
	<class name=".......Dept" table="..dept..">
		<id name="did" column="did" type="int">
			<generator class="assigned"/>
		</id>

		<property name="pname" column="pname" type="java.lang.String"/>		
	</class>
</hibernate-mapping> 

2.也可以在一端配置

public class User{
       private int uid;
       private String uname;

      ..............

   }

   public class Dept {
	private int did;
	private String dname;
        private Set<User> users = new HashSet<User>();

      ..   ..... 
   }


   <hibernate-mapping>
	<class name=".......User" table="..user..">
		<id name="uid" column="uid" type="int">
			<generator class="assigned"/>
		</id>

		<property name="name" column="name" type="java.lang.String"/>
		
	</class>
</hibernate-mapping> 

<hibernate-mapping>
	<class name=".......Dept" table="dept">
		<id name="did" column="did" type="int">
			<generator class="assigned"/>
		</id>

		<property name="dname" column="dname" type="java.lang.String"/>

		<set name="users" inverse="true" lazy="true" cascade="all">
			<key>
				<column name="did" not-null="true"/>
			</key>
			<one-to-many class="........User"/>
		</set>
	</class>
</hibernate-mapping>

3.双向就都配置们就好了。。。。

[wilburwei]

User表：uid,uname,did
Dept表：did,pname

pid外键
1.可以在User端配多对一

   public class User{
       private int uid;
       private String uname;
       private Dept dept;

      ..............

   }

   public class Dept {
	private int did;
	private String dname;

      ..   ..... 
   }


   <hibernate-mapping>
	<class name=".......User" table="..user..">
		<id name="uid" column="uid" type="int">
			<generator class="assigned"/>
		</id>

		<property name="uname" column="uname" type="java.lang.String"/>

		<many-to-one name="dept" class=".........Dept" column="pid" unique="true"/>
		
	</class>
</hibernate-mapping> 

<hibernate-mapping>
	<class name=".......Dept" table="..dept..">
		<id name="did" column="did" type="int">
			<generator class="assigned"/>
		</id>

		<property name="pname" column="pname" type="java.lang.String"/>		
	</class>
</hibernate-mapping> 

2.也可以在一端配置

public class User{
       private int uid;
       private String uname;

      ..............

   }

   public class Dept {
	private int did;
	private String dname;
        private Set<User> users = new HashSet<User>();

      ..   ..... 
   }


   <hibernate-mapping>
	<class name=".......User" table="..user..">
		<id name="uid" column="uid" type="int">
			<generator class="assigned"/>
		</id>

		<property name="name" column="name" type="java.lang.String"/>
		
	</class>
</hibernate-mapping> 

<hibernate-mapping>
	<class name=".......Dept" table="dept">
		<id name="did" column="did" type="int">
			<generator class="assigned"/>
		</id>

		<property name="dname" column="dname" type="java.lang.String"/>

		<set name="users" inverse="true" lazy="true" cascade="all">
			<key>
				<column name="did" not-null="true"/>
			</key>
			<one-to-many class="........User"/>
		</set>
	</class>
</hibernate-mapping>

3.双向就都配置们就好了。。。。