4:44 p.m.
In the new metamodel code, it appears that both "Attribute" and
"Value" bindings are modelled using AttributeBinding. The places I've seen
references to "Value" bindings (EntityIdentifier, Discriminator) don't
necessarily have a domain representation.
I'm working on @IdClass, and this an example where the IdClass itself does not have a
representation in the domain model.
I'd like to make some improvements.
Steve, (and anyone else interested) please take a look at https://gist.github.com/981804
and let me know if you see anything inherently wrong with my approach, or if you have some
suggestions.
Thanks,
Gail
8:18 p.m.
Well there are 2 orthogonal distinctions here.
1) Physical versus virtual attributes: some values in the relational
model correspond to attributes physically defined on the domain model,
some do not.
2) Then there is the question of cardinality of the value (one column or
multiple).
In general combining 2 orthogonal set of options each with 2 options is
going to give you 4 results: combining (A,B) and (Y,Z) is going to
result in [A,Y], [A,Z], [B,Y], [B,Z].
Not sure what you mean by "I'd like to propose only adding true
"Attribute" bindings (including those contained in to
attributeBindingMap)." but that statement scares me. We absolutely need
to be able to track the bindings for virtual attributes.
Also, I do not like the terms "value binding" and "attribute binding",
at all. You are mixing terms from different concepts. It is confusing.
I much prefer AttributeBinding and VirtualAttributeBinding or
something similar that says "this is an attribute binding, but for a
special attribute that does not exist on the domain model".
On 05/19/2011 04:44 PM, Gail Badner wrote:
In the new metamodel code, it appears that both "Attribute"
and "Value" bindings are modelled using AttributeBinding. The places I've
seen references to "Value" bindings (EntityIdentifier, Discriminator) don't
necessarily have a domain representation.
I'm working on @IdClass, and this an example where the IdClass itself does not have a
representation in the domain model.
I'd like to make some improvements.
Steve, (and anyone else interested) please take a look at https://gist.github.com/981804
and let me know if you see anything inherently wrong with my approach, or if you have some
suggestions.
Thanks,
Gail
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Steve Ebersole <steve(a)hibernate.org>
http://hibernate.org
2:37 a.m.
On Fri, 20 May 2011 03:18:54 +0200, Steve Ebersole <steve(a)hibernate.org>
wrote:
Also, I do not like the terms "value binding" and
"attribute binding",
at all. You are mixing terms from different concepts. It is confusing.
I much prefer AttributeBinding and VirtualAttributeBinding or
something similar that says "this is an attribute binding, but for a
special attribute that does not exist on the domain model".
I have a hard time making a judgment since I don't know exactly what and
how things are then wired up in the persisters.
I like the distinction between AttributeBinding and VirtualAttributeBinding
though. If not reflected in code we should still stick to this terms to
talk about this particular distinction.
One way or the other though we have to be able to move forward now. So far
a lot of work from the annotation side could be done decoupled from the
metamodel,
but now we are really in a stage we would need to see how things like
joins, components
and the missing associations are supposed to work.
--Hardy
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2 comments
3 participants
participants (3)
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Gail Badner -
Hardy Ferentschik -
Steve Ebersole