Re: Mapping between schemas

Butler, Mark wrote:

>(a) We can create a property called creator, and then subproperties called
>role, attribution, personal_name and corporate_name. If we do this, we are
>making the assumption that an image has exactly one creator.
>  
>
Why can't the property be repeated?  I wouldn't assume any specific 
relationship between the property and the subproperty.  You can still 
represent many creators, you just can't tell if each subproperty is 
unique or is related to the others.   e.g:

<A> :creator.personalName "Leonardo,da Vinci",
    :creator.corporateName "School of Leonardo".

There is nothing either explicit in subproperties that links "School of 
Leonardo" to "Leonardo,da Vinci".  As a result these two items already 
represent multiple creators.

>(b) Alternatively we can create a class called Creator. Now our Image
>instance has one or more properties called hasCreator, each of which points
>to an instance of Creator. The properties roles, attribution, personal_name
>and corporate_name all have domain Creator. Now images can have multiple
>creators, because each creator is an independent object, rather than a
>property value. 
>
>Now lets consider the mapping:
>
>1. It's fairly straightforward to map a:role, a:attribution, a:personal_name
>and a:corporate_name onto their respective counterparts in b.
>
>2. Mapping b on to a is may be more difficult, if an image does have
>multiple creators.
>
Mapping b on to a is hard period.  I would argue that there simply isn't 
enough information to indicate how subproperties should be grouped 
together whether there is one, or several 'creators'.

>
>3. Mapping between creator is difficult, because it is a property in a and a
>class in b.
>
>any thoughts?
>
>Dr Mark H. Butler
>Research Scientist                HP Labs Bristol
>mark-h_butler@hp.com
>Internet: http://www-uk.hpl.hp.com/people/marbut/
>  
>


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Received on Tuesday, 7 October 2003 14:56:09 UTC