I have a class BioSequence has a joined-subclass called Contig.
I have a class Feature that has a property 'sequence' of type BioSequence.

1) I would like to do a query on a Feature and include properties of Contig in the where clause. Right now I am doing it like this:

from Feature f, Contig c where f.sequence.id=c.id and c.number>4

Is there a better way that does not require the join in HQL?

2) The above works when what I want is an inner join, but it does not work in the case of an outer join.

For example, I would like to query all BioSequences except those that are instances of the Contig class where c.number>4

Thanks in advance,

Dave