[topicmapmail] Re: Topic Map - scope

[Thomas B. Passin]

Dichev, Christo wrote:

> The straightforward approach to differentiating the units for more
> able and less able students  is to define to units (unit-1 and unit-2)
> and link them using an association  (intended-for) - somethinh like
> the following:
> 
> <topic id="unit-1">
>   <instanceOf><topicRef xlink:href="#leson"/></instanceOf>
>   <baseName>
>     <baseNameString> First Unit</baseNameString>
>   </baseName>
>   <occurrence>
>     <instanceOf><topicRef xlink:href="#webpage"/></instanceOf>
>     <resourceRef 
> xlink:href="http://wssu.edu/faculty/dichevc/ex/sect2.html"/>
>   </occurrence>
> </topic>
> 
> <topic id="unit-2">
>   <instanceOf><topicRef xlink:href="#leson"/></instanceOf>
>   <baseName>
>     <baseNameString> Second Unit</baseNameString>
>   </baseName>
>   <occurrence>
>     <instanceOf><topicRef xlink:href="#webpage"/></instanceOf>
>     <resourceRef 
> xlink:href="http://wssu.edu/faculty/dichevc/ex/sect1.htm"/>
>   </occurrence>
> </topic>
> 
> <association>
>     <instanceOf>
>       <topicRef xlink:href="#intended-for"/>
>     </instanceOf>
>     <member>
>       <roleSpec>
>         <topicRef xlink:href="#average-student"/>
>       </roleSpec>
>    <topicRef xlink:href="#unit-1"/>
>     </member>
>     <member>
>       <roleSpec>
>         <topicRef xlink:href="#good-student"/>
>       </roleSpec>
>    <topicRef xlink:href="#unit-2"/>
>     </member>
>   </association>
> 
> My first intention was to combine unit-1 and unit-2 into a single
> unit and to achieve the same effect, using scope. That's where I
> got stuck.
> 

Why do you want to try combining them?  Is it just to try out scopes or 
because you see some modeling advantage in doing so?  Personally, I 
would think that it would be better to say there is one unit for a 
course, and by using an association say that it has one web page for 
average students and one for good students.  That's me, but of course I 
do not really know your problem.

By using scopes, you would be saying that there is one unit, but if you 
look at it in the context of an average student, the web page for that 
unit has one URL (and its set of content), while in the context of a 
good student, it has a different URL (and its own set of content).  If 
you think that expresses what you need, go ahead and use scope do 
distinguish the two cases.

I think that you are interested in expressing something stronger, for 
which as association would be better than scopes, but only you can say.

> Please excuse me if I am asking something too trivial.

Not at all.

Cheers,

Tom P