Mapping two tables 0..n in Hibernate
- by simon
I have a table Users
CREATE TABLE "USERS" (
"ID" NUMBER NOT NULL ,
"LOGINNAME" VARCHAR2 (150) NOT NULL )
and I have a second table SpecialUsers. No UserId can occur twice in the SpecialUsers table, and only a small subset of the ids of users in the Users table are contained in the SpecialUsers table.
CREATE TABLE "SPECIALUSERS" (
"USERID" NUMBER NOT NULL,
CONSTRAINT "PK_SPECIALUSERS" PRIMARY KEY ("USERID") )
ALTER TABLE "SPECIALUSERS" ADD CONSTRAINT "FK_SPECIALUSERS_USERID" FOREIGN KEY ("USERID")
REFERENCES "USERS" ("ID")
/
Mapping the Users table in Hibernate works ok
<hibernate-mapping package="com.initech.domain">
<class name="com.initech.User" table="USERS">
<id name="id" column="ID" type="java.lang.Long">
<meta attribute="use-in-tostring">true</meta>
<generator class="sequence">
<param name="sequence">SEQ_USERS_ID</param>
</generator>
</id>
<property name="loginName" column="LOGINNAME" type="java.lang.String" not-null="true">
<meta attribute="use-in-tostring">true</meta>
</property>
</class>
</hibernate-mapping>
But I'm struggling in creating the mapping for the SpecialUsers table. All the examples (e.g. in Hibernate documentation) in Internet I found don't have this type of self-reference. I tried a mapping like this:
<hibernate-mapping package="com.initech.domain">
<class name="com.initech.User" table="SPECIALUSERS">
<id name="id" column="USERID">
<meta attribute="use-in-tostring">true</meta>
<generator class="foreign">
<param name="property">user</param>
</generator>
</id>
<one-to-one name="user" class="User"/>
</class>
</hibernate-mapping>
but got the error
Invocation of init method failed; nested exception is org.hibernate.DuplicateMappingException:
Duplicate class/entity mapping com.initech.User
How should I map the SpecialUsers table? What I need on the application level is a list of the User objects contained in the SpecialUsers table.
