On Fri, 2008-07-04 Peter Gummer wrote:
> Now I need to be clear about something ;-)
>
> I'm 99% certain, Thomas, that Tim is talking about circular
> references in
> the class model, not in the instance graph.
True.
> Apparently it gives the Python interpreter an apoplexy when it
> tries to resolve references that it has discovered yet. But as
> I mentioned in my earlier email, a bit of googling suggests
> that Python does have ways of working around this.
>
> Let's see what Tim thinks.
>
Let's see if I can add some context and explain my complaint a bit
better.
An Archetype instance is a container and it has 6 items in it. Some are
required, some optional. Some of those are containers as well. You can
visualize this by thinking of a directory tree:
Archetype
adl_version
archetype-id
uid
concept
parent_archetype_id
definition
ontology
invariants
revision_history (inherited)
Sticking with the ontology issue:
Archetype
adl_version
archetype-id
uid
concept
parent_archetype_id
definition
ontology
terminologies_available
specialisation_depth
term_codes
constraint_codes
term_attribute_names
parent_archetype_id
invariants
revision_history (inherited)
The issue here is the REQUIRED attribute parent_archetype_id. The
description is; Archetype which owns this ontology. Intuitively (to me
anyway) this would indicate that I would assign the OID of the parent
Archetype to this attribute. However, the specifications call for the
attribute to be of the type 'Archetype' and it can't be just any
archetype, it is supposed to be the Archetype containing this ontology.
so I would have a repeating tree like this:
Archetype
adl_version
archetype-id
uid
concept
parent_archetype_id
definition
ontology
terminologies_available
specialisation_depth
term_codes
constraint_codes
term_attribute_names
parent_archetype_id
Archetype
adl_version
archetype-id
uid
concept
parent_archetype_id
definition
ontology
terminologies_available
specialisation_depth
term_codes
constraint_codes
term_attribute_names
parent_archetype_id
... (repeat infinitely)
invariants
revision_history (inherited)
invariants
revision_history (inherited)
So my suggestion is that ARCHETYPE.ontology.parent_archetype_id be of a
'type' that represents the OID of the parent and NOT the parent itself.
Cheers,
Tim
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