Hi,

I am having great difficulty trying to model the following classes using Hibernate. I do feel it may not be possible to do. Please help.


class Address {
... // typical address attributes
}

class CustomerAddress extends Address {
String addressRef; // e.g. home, work, friend
int timeAtAddress;
...
}

class Supplier {
Address address;
...
}

class Customer {
Set addresses;
...
}

A Supplier will have one address.
A Customer will have 1 or more CustomerAddress instances.
(Later, there may be further subclasses of Address)
--------------------------------------------------------

At the database, I would expect something like:

[Supplier] 1 ------------ 1 [Address]

[Customer] 1 ----------<- 1..n [Address(CustomerAddress)]


I have been totally baffled trying to write the Hibernate mapping file(s) for these classes.

The above may not be possible to do. Any help would be greatly appreciated.

I am using Hibernate versation 2.1.1 and may easily use a later version if it helps.

Thanks in advance,

Usman

of course it is possible, what db schema do you have?

Thank you for the quick reply. I apologise for not supplying enough information.

I do not have a DB schema yet. In fact, it is the DB schema that is confusing me. I'll try to explain next.

I am modelling a class hierarchy in UML from which I intend to write the Hibernate mapping files. I will use the SchemaExport tool to generate the database tables and relationships from the .hbm files. Hence, I am hoping this SchemaExport tool will create the necessary tables and relationships in the MySQL database I am using rather than I directly working at the database level.

The following is the outline java code for the UML hierarchy:

public class Address {
private int buildingNumber;
private string street;
private string town;
private string region;
}

public class CustomerAddress extends Address {
private date dateMovedIn;
private string addressType;
private int noOfYearsAtAddress;
}

public class Customer {
private string customerRef;
private string forename;
private string surname;
private set customerAddresses;

//set of CustomerAddress instances, not base class Address:
private Set customeraddresses;
}

public class Supplier {
private string supplierRef;
private string name;
private Address supplierAddress;

private Address address;
}


The following are my .hbm stubs and are incomplete - this is where I am stuck:


<class name="mypkg.Customer"
table="Customer" >
<id
name="id"
type="java.lang.Integer"
unsaved-value="0" >
<generator class="native" />
</id>

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

... here I need some kind of reference to the CustomerAddress class?
</class>

<class name="mypkg.Supplier"
table="Supplier" >
<id
name="id"
type="java.lang.Integer"
unsaved-value="0" >
<generator class="native" />
</id>

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

<!-- is the following correct? -->
<many-to-one name="address"
column="ADDRESS"
class="Address"/>
</class>

<class name="mypkg.Address"
table="Address" >
<id
name="id"
type="java.lang.Integer"
unsaved-value="0" >
<generator class="native" />
</id>

<property
name="street"
type="java.lang.String" />
...
<subclass
name="mypkg.CustomerAddress"
discriminator-value="CUSTOMERADDRESS"
>
<property
name="dateMovedIn"
type="java.util.Date" />
<property
name="addressType"
type="java.lang.String" />
</subclass>
</class>

What do I specify in the Customer mapping to define the Customer----<-CustomerAddress relationship?
How I get the Customer to reference CustomerAddress rather than Address?


Thank you,

Usman

<class name="mypkg.Customer"
table="Customer" >
<set name="customeraddresses">
<key name=""/>
<one-to-many class="CustomerAddress"/>
</set>


<class name="mypkg.Supplier"
table="Supplier" >

<!-- is the following correct? --> <!-- yes -->
<many-to-one name="address"
column="ADDRESS"
class="Address"/>
</class>

Thanks guys for all your help.