Hi,

I'm currently trying to map this kind of relations:

Computer - 1 -------------- N - InstalledSoftware
Computer - 1 -------------- N - InstallableSoftware
Computer - 1 -------------- N - EquivalentSoftware


In fact such relations are equivalent to the next one:

Computer - 1 -------------- N - software

where sofware is the generic entity for (InstalledSoftware,InstallableSoftware,EquivalentSoftware).
These 3 specifics entities all have the same attributes...

The only way I find to map this relation is to add a discriminator
column in the sofware table:
TYPE=I for Installed
TYPE=A for installable
TYPE=E for Equivalent...
and declaring a OneToMany relation between Computer and software... and finally implementing methods like:



I'm not sure this the best solution...
any ideas are welcome ;-)

(I'm interested in hibernate solution too)

Something like the following should work:

Hrm... maybe I didn't quite understand your original post...

If you had a superclass Software, which is subclassed by InstalledSoftware, etcetera, then you could do the following:

@Entity
public class Software {
// ...
}

@Entity
public class InstalledSoftware
extends Software
{
// ...
}

@Entity
public class InstallableSoftware
extends Software
{
// ...
}

@Entity
public class EquivalentSoftware
extends Software
{
// ...
}

Then you could just set up three simple OneToMany relations on Computer:

@Entity
public class Computer
{

@OneToMany
private Set<InstalledSoftware> installedSoftware ;

@OneToMany
private Set<InstallableSoftware> installableSoftware ;


// etc...
}