one-to-many foreign key issue

micheleolivo · **Joined:** Tue Aug 13, 2013 4:59 pm **Posts:** 2

Hello, i have this two tables in PostgreSQL:

Code:

CREATE TABLE COLLEGIO (
   codColl NUMERIC(4,0) NOT NULL,
   provincia VARCHAR(35) NOT NULL,
   /* Other fileds */
   PRIMARY KEY (codColl, provincia)
);
CREATE TABLE ELETTORE (
   codEl VARCHAR(16) NOT NULL,
   /* Other fileds */
   PRIMARY KEY (codEl),
   FOREIGN KEY (codColl, provincia) REFERENCES COLLEGIO (codColl, provincia)
);

I have created the classes with these XML files:

Code:

<class name="Collegio" table="COLLEGIO">
    <composite-id name="collegioKey" class="entities.keys.CollegioKey">
           <key-property type="int" name="codColl"/>
           <key-property type="string" name="provincia"/>
    </composite-id>
    <set name="elettori" table="ELETTORE" inverse="true" lazy="true" fetch="select">
        <key column="codel" not-null="true"/>
        <one-to-many class="entities.Elettore" />
    </set>
</class>
<class name="Elettore" table="ELETTORE">
    <id name="codEl" column="codEl">
        <generator class="assigned" />
    </id>

    <many-to-one name="collegio" class="entities.Collegio" fetch="select">
        <column name="codcoll" not-null="true"/>
        <column name="provincia" not-null="true"/>
    </many-to-one>
</class>

But when i try to run the project (for example for listing the content of the table "COLLEGIO") hibrenate give me this error:

Code:

org.hibernate.MappingException: Foreign key (FK_da1lkg53is2jg7wmcddlarf6s:ELETTORE [codel])) must have same number of columns as the referenced primary key (COLLEGIO [codColl,provincia])

What I have done wrong?

Ajit Singh · **Joined:** Wed Feb 06, 2013 2:43 am **Posts:** 46

You need to have these two columns(codColl, provincia) also in your table ELETTORE to make use of foreign key.

CREATE TABLE ELETTORE (
codEl VARCHAR(16) NOT NULL,
codColl NUMERIC(4,0) NOT NULL,
provincia VARCHAR(35) NOT NULL,
/* Other fileds */
PRIMARY KEY (codEl),
FOREIGN KEY (codColl, provincia) REFERENCES COLLEGIO (codColl, provincia)
);

And then the mapping as :

<composite-id name="id" class="ELETTORE">
<key-property name="codEl" column="codEl" type="int"/>
<key-many-to-one name="Collegio" class="entities.Collegio">
<column name="first_name"/>
<column name="last_name"/>
</key-many-to-one>
</composite-id>