Re: Interaction model vs data model

El 24/01/13 16:53, Roger Menday escribió:
>
>>>> For what it's worth, section 5.2.1 of the LDP spec [2] states that "A
>>>> Linked Data Platform Container must also be a conformant Linked Data
>>>> Platform Resource." I've always read that as meaning that an LDPC is an
>>>> LDPR.
>>>
>>>
>>> In the data model,
>>>
>>> LDPR:
>>>     - has a RDF representation
>>>
>>> LDPC:
>>>     - has a RDF representation
>>>     - has a set of reserved properties with their semantics defined by the
>>> protocol
>>>     - contains some protocol data
>>>
>>> so LDPC is a specialization of LDPR.
>>>
>>> In the interaction model,
>>>
>>> GET:
>>>    LDPR - returns the current state.
>>>    LDPC - returns the current state. In addition, provides mechanisms to
>>> retrieve only part of the state (non-member properties) and provides
>>> additional features like paging, ordering based a special property
>>> (membership predicate).
>>>
>>> PUT:
>>>    LDPR - updates the current state
>>>    LDPC - Only part of the state may be updated via
>>> <containerURL>?non-member-properties. The rest of the state is managed by
>>> the server.
>>>
>>> POST:
>>>    LDPR - updates it's state by appending new triples ?
>>>    LDPC - creates new resources
>>
>> and adds it to the membership
>>
>>>
>>> DELETE:
>>>    LDPR - deletes itself
>>>    LDPC - deletes itself and any resources contained by it
>>>
>>> LDPC and LDPR have different interaction models but I suppose a
>>> specialization can have a different interaction model.
>>>
>>> Best Regards,
>>> Nandana
>>
>> This is simple and clear to me, then again it is the current state of
>> the spec (mostly). Nice summary
>
> It could be that I am reading the spec wrong, but, my understanding is that when a LDPR has only one LDPC, it can be that both are the same resource. In that case where does that leave the HTTP operations in the above - esp. PUT and POST ?

Dear all,

If an LDPC is an LDPR, then its behaviour should be at least the same as 
that of an LDPR.

Here you have Nandana's summary updated so that an LDPC has the same 
behaviour as an LDPR with "In addition" clauses.

The updates are:
.- I have tried to define a common behaviour regarding PUT and POST, 
which was what Roger mentions in his email. Now, and LDPC behaves like 
an LDPR.
.- Re-reading the HTTP 1.1 spec (http://www.ietf.org/rfc/rfc2616.txt) 
once you POST to a resource URI, "the posted entity is subordinate to 
that URI", and the examples given are equivalent to our composition 
approach. So, I see two options: or the server contains some background 
information and converts the LDPR into an LDPC (which will still behave 
as an LDPR) or the server ignores the request (or it fails). I don't see 
the case of appending the triples as mentioned in ISSUE-45.


LDPC is a specialization of LDPR.

Representation:
    LDPR - has an RDF representation
    LDPC - has a RDF representation
         - In addition: has a set of reserved properties with their 
semantics defined by the protocol
         - In addition: contains some protocol data

In the interaction model,

GET:
    LDPR - returns the current state.
    LDPC - returns the current state.
         - In addition, provides mechanisms to retrieve only part of the 
state (non-member properties)
         - In addition, provides additional features like paging, 
ordering based a special property (membership predicate)

PUT:
    LDPR - updates the current state
    LDPC - updates the current state
         - In addition, restricts the update of members in updates
         - In addition, only part of the state may be updated via 
<containerURL>?non-member-properties

POST:
    LDPR - does nothing
    LDPC - does nothing
         - In addition, creates a new resource and adds it to the membership

DELETE:
    LDPR - deletes itself
    LDPC - deletes itself
         - In addition, any resources contained by it are deleted

Kind regards,

-- 

Dr. Raúl García Castro
http://delicias.dia.fi.upm.es/~rgarcia/

Ontology Engineering Group
Departamento de Inteligencia Artificial
Universidad Politécnica de Madrid
Campus de Montegancedo, s/n - Boadilla del Monte - 28660 Madrid
Phone: +34 91 336 36 70 - Fax: +34 91 352 48 19

Received on Friday, 25 January 2013 15:23:21 UTC