Re: Proposal for containers

Hi Steve:
These are good questions.  I am not an RDF expert.  Perhaps some of
the others can fill in the blanks.
All the best, Ashok

On 1/30/2013 2:18 PM, Steve Battle wrote:
> Ashok,
>
> LDP resources (including containers) are defined as "web resources that describe their state using RDF".
> What are your thoughts on how the relationship between the container and the contained is represented in RDF? This being part of it's state.
>
> My concern, as always, is that if predicates like rdfs:member are allowed for composition then this makes it difficult to distinguish between a resource POSTed to the container (as in B.), and a resource _linked_ to the container using rdfs:member (as in F.). I advocate use of a distinct composition property (eg. ldp:contains, or ldp:owns, or ldp:manages) to avoid this confusion between composition and aggregation.
>
> This is an extension of your proposal below, NOT an alternative proposal.
>
> Steve.
>
> On 30 Jan 2013, at 15:23, Ashok Malhotra<ashok.malhotra@oracle.com>  wrote:
>
>> OK.  Here goes
>>
>> Container Model
>>
>> A. Containers can contain containers
>> Containers are LDPRs and should
>> be added to contianers like any other LDPR.
>>
>> B. To add a container to a container, POST a (child) container
>> representation to a (parent) container.
>>
>> C. Thus, a contianer can contain a mix of members and comtainers.
>> (Some of the members may be links to LDPRs.)
>>
>> D. If you GET all members of a
>> container that has nested components, you get all the contents,
>> members and containers at the top level.  That is, you do not get nested
>> components.
>>
>> Composition and Aggregation
>>
>> E. If you delete a container you delete everything it contains.
>> For nested containers this leads to a cascaded delete.
>>
>> F. If you do not want a member to be deleted when the container is deleted,
>> do not include the member in the containers but rather include a link to the
>> member in the container.
>>
>> E and F follow the AtomPub model.  There are other proposals
>> -- distinct containers and aggregators, an attribute to distinguish
>> between containers and aggregators.  We can debate these separately
>> from A, B, C, D
>>
>>
>> All the best, Ashok
>

Received on Wednesday, 30 January 2013 21:52:44 UTC