Hi,
I have a problem trying to persist two objects that are related through an indirection
table. This is what my tables look like:
-----
PERSON
id
firstname
lastname
...
ADDRESS
id
street
housenr
...
PERSON_ADDRESS
person_id
address_id
-----
I have chosen for this construction, because COMPANY can have multiple addresses too,
so I don't want a column person_id in ADDRESS. One address doesn't have to be
available for multiple PERSON's or COMPANY's or whatever, so it actually is more of a
1:n relationship using an indirection table. So PERSON_ADDRESS will often contain the
same person_id multiple times, but not the same address_id.
I've read the tutorials, but I don't get it to work. I'll show (a fragment of) our
repository_user.xml:
-----
<class-descriptor
class="nl.bergland.codamo.Address"
table="bit_Address"
>
<field-descriptor
name="id"
column="id"
jdbc-type="INTEGER"
primarykey="true"
length="11"
>
</field-descriptor>
<field-descriptor
name="street"
column="street"
jdbc-type="VARCHAR"
length="64"
>
</field-descriptor>
<field-descriptor
name="houseNr"
column="houseNr"
jdbc-type="VARCHAR"
length="16"
>
</field-descriptor>
</class-descriptor>
<class-descriptor
class="nl.bergland.codamo.Person"
table="bit_Person"
>
<field-descriptor
name="id"
column="id"
jdbc-type="INTEGER"
primarykey="true"
length="11"
>
</field-descriptor>
<field-descriptor
name="firstName"
column="firstName"
jdbc-type="VARCHAR"
length="24"
>
</field-descriptor>
<field-descriptor
name="lastName"
column="lastName"
jdbc-type="VARCHAR"
length="24"
>
</field-descriptor>
<collection-descriptor
name="addresses"
element-class-ref="nl.bergland.codamo.Address"
indirection-table="bit_PersonAddress"
auto-retrieve="true"
auto-update="true"
auto-delete="true"
>
<fk-pointing-to-this-class column="personId"/>
<fk-pointing-to-element-class column="addressId"/>
</collection-descriptor>
</class-descriptor>
-----
The generated tables in mysql seem to be ok with me (we actually use OjbDoclet to
generate the repository.xml and the SQL) and insertion of a PERSON works fine.
However, when we create a new person, add a new Address to it and try to save the
person, the following happens:
A new record gets created for PERSON fine
A new record gets created for ADDRESS fine, but when I set auto-update to true, 2 get
created??
A new record gets created for PERSON_ADDRESS, but both the columns person_id and
address_id are set to 0.
Our save code looks something like this:
-----
Person person = new Person;
person.getAddresses().add(new Address());
Implementation impl = OJB.getInstance();
Database db = impl.newDatabase();
db.open("default", Database.OPEN_READ_WRITE);
Transaction tx = impl.newTransaction();
tx.begin();
// establish database locks on all root dataobjects
tx.lock(person, Transaction.WRITE);
// set person and address values
// ...
tx.commit();
db.close();
-----
A lot of info for a first-time post, I hope this problem sounds familiar to someone
here.
Thanks,
-Stijn
