OK, I am trying to map a weak entity set in my mapping files.

I have 2 tables:

User
- id (primary key)
- ...


Type
- type_id
- User_id
Primary key(type_id, User_id)

When I use it like this, I enforce the fact that there is only one type possible per User.

Mapping file of Type:

<hibernate-mapping>

<class name="Type" table="type">
<composite-id name="id" class="TypeKey">
<key-property name="gebruikerId" column="user_ID" type="integer"/>
<key-property name="typeId" column="type_ID" type="string"/>
</composite-id>

<property name="naam" column="naam" type="string" not-null="true" />
<property name="machtigingen" column="machtigingen" type="string" not-null="true" />
<set name="User" inverse="true">
<key column="ID"/>
<one-to-many class="User"/>
</set>
</class>
</hibernate-mapping>

Relevant part of Use mapping:

<class name="User" table="User">
.
.
.
<many-to-one name="type"/>
</class>

But when I try to use this, I always get an error about:
"Foreign key must have same number of columns as the referenced primary key"

I understand why he is saying this, i only make a reference to one of the primary keys, but I have no idea how to solve this. I can't find an example that is comparable to mine. I've saw complex solutions using <key-many-to-one> ... But that all looked very strange.

Any suggestions about how my mapping file should look ?

Thx

A comment and a question--

1) Assuming table TYPE represents user types, you should make TYPE a lookup table (read-only) and put a TYPE_ID in table USER instead of the other way around (your schema).

2) Also, if you have a TYPE_ID in table TYPE, why can't that id alone be a unique id for Type entities? (since you've already named it "type id"...)

Whatever your reason, you can try adding a surrogate key to Type table:


Now the mapping should look like:


Of course TYPE_ID now becomes just another property for Type, but if 1) is what you're trying to do, then just get rid of TYPE_ID and you're all set.

jd