Hi,

I have these tables:


In other words, a component may have a set of dependent components. These can be of any type (from the Component_Type table).

I would like, in Object Oriented code, to do something like:
Set dependentComponentVersions = (Set)version.getDependencies().get( componentType );

This would return a set of dependent component versions, from a specific component versions. The set of dependent component versions would contains only dependent component versions of a certain type.

With Hibernate:
I can't see a way to use a map collection having sets as its elements.
I don't see how I could have my mapping files to accomplish what I just described

Is there a way? Any comments on the way we modelised this in the DB?

Thank you,

You can't map nested collections. You have to use an intermediate class if you want to do so.

Well,

I know how I could return the complete list of dependent versions for a version....

Set dependentVersion version.getDependencies();

Having a Set mapped with "many-to-many" (or with an intermediate class)

But, then I would have to filter that set for component of the specific type I want. I would like to avoid this.

I would like version.getDependencies() to return a Map collection. The index would be a componentType object and the element would be a Set of DependentVersion objects (here is the intermediate class).

Is it possible to accomplish this with hibernate? Having a Map collection returning a Set of entities?

Thanks

No, not possible. Hibernate managed Maps can contain only "value" elements or mapped entities, not Sets.

Ok,

Do you have any suggestion for my specific case then?

How would you handle that situation? Should I use session.filter() to finally have a list of the dependent component versions of a specific type?

Any suggestion would help.

Thanks again for your quick replies,

Yes, perfect. I'm now using a Class (and a hbm mapping) for every table in the relational model. This resolved everything and gives me more power at querying the information i need.

Since I have a surrogate key for every tables in the relational model, this was essential anyway.