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Re: [ontolog-forum] Accommodating legacy software

To: ontolog-forum@xxxxxxxxxxxxxxxx
From: Kingsley Idehen <kidehen@xxxxxxxxxxxxxx>
Date: Wed, 05 Sep 2012 13:13:39 -0400
Message-id: <50478843.9090300@xxxxxxxxxxxxxx>
On 9/5/12 8:06 AM, Michael Brunnbauer wrote:
> Hello Kingsley,
>
> I think doug really has a point here. Imagine how simple the conversion of a
> RDB to RDF would be if we had n-ary relations. Of course the usefulness
> of such an 1:1 conversion is doubtful but the entry threshold would be lower.    (01)

Sorta.    (02)

We've have an RDBMS to RDF mapper that has an RDBMS at the base [1][2], 
it showcases the power of n-arity which is easy for an RDBMS to deal. 
Where I differ from Doug is that I am looking at the basic foundation of 
factual expression being a 3-tuple or 4-tuple (but this lacks 
standardization at this time, for instance we do things in our product 
that's  different from others re. role of the 4th element).    (03)

When trying to get Web users to express and share facts, I believe 
3-tuples are adequate. A nice example is the ability to express and 
share facts via Turtle documents [3]. We can't ask Web users to start 
with n-tuples, it won't work.    (04)

My comment above doesn't imply that other software products can't be put 
to use as part of the processing pipeline e.g., a crawler and indexer 
that offers additional value.    (05)

I am simply fighting for a starting point that maps closely to mental 
model of most humans.    (06)

>
> Am I right that you are OK with quick and simple conversions to RDF where the
> real value is added via mappings later ?    (07)

Absolutely!    (08)

> Some of your data integration tools
> probably work this way.    (09)

Exactly!
>
> I have wondered about the restriction to triples publicly several times and
> never got an answer about the reasons for it. Was it for simplicity of
> implementation ?    (010)

Simplicity en route to bootstrap.    (011)

> Do we really know that n-tuples would be a pain ?    (012)

Yes, look at blank nodes in RDF [4][5]. Even look at multi-value types 
in RDBMS products. The results are always the same, too confusing for 
end-users to get going.    (013)

Links:    (014)

1. http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VOSSQLRDF -- 
mapping via a Meta Language between an RDBMS and RDF    (015)

2. http://bit.ly/Q7D9jw -- some posts showcasing a live instance of our 
hybrid data server explore which shows effects of navigation over  
intensional and extensional dimensions (even shows the effects of 
different kinds of hyperlinks as super keys etc..)    (016)

3. http://bit.ly/RJzd9S -- why Turtle is effective for enabling mass 
curation and dissemination of facts, at Web-scale.    (017)

4. http://www.w3.org/TR/turtle/ -- Turtle spec    (018)

5. http://www.w3.org/2007/02/turtle/primer/#structuredproperties -- 
Turtle Primer .    (019)

Kingsley
>
> Regards,
>
> Michael Brunnbauer
>
> On Wed, Sep 05, 2012 at 07:22:56AM -0400, Kingsley Idehen wrote:
>> On 9/5/12 12:02 AM, doug foxvog wrote:
>>> On Tue, September 4, 2012 17:02, Kingsley Idehen wrote:
>>>> On 9/4/12 3:41 PM, doug foxvog wrote:
>>>>> On Tue, September 4, 2012 12:34, Kingsley Idehen wrote:
>>> ...
>>>
>>>>>> I believe Data denotes Subject Observation.
>>>>>> I believe all observations are comprised of:
>>>>>> 1. a subject
>>>>>> 2. subject attributes
>>>>>> 3. subject attribute values.
>>> ...
>>>>> One common type of observation is that A is between B and C.
>>>>> How would you express this with a single triple?    8)#
>>>> I would state that A is between B. A is Between C. Then I would define
>>>> the semantics of  the  'Between' predicate  .
>>> !??
>>> Let's explore this:
>>>    (and
>>>       (between   10 5 11)
>>>       (between   10 4 11)
>>>       (between   10 6 11)
>>>       (between   10 7 11))
>>> Using the KI translator this becomes:
>>>    AND
>>>      10 is between 5
>>>      10 is between 11
>>>      10 is between 4
>>>      10 is between 11
>>>      10 is between 6
>>>      10 is between 11
>>>      10 is between 7
>>>      10 is between 11.
>>>
>>> What semantics does the between predicate have?
>> And that isn't what I was conveying to you. Basically, at what point did
>> you indicate we where dealing with typed literals? You said A between B
>> and B between C.  Why on earth should I assume A, B, and C are typed
>> literals? Just because you used the literal 'Between' in some kind of
>> fuzzy context?
>>
>> RDF is pretty clear about the semantics for typed literals.
>>> How about the quaternary predicate, isBetweenOnPath?
>>> Can you express the following with triples:
>>>
>>> (and
>>>    (isBetweenOnPath WashingtonDC Maryland Virginia I95)
>>>    (not (isBetweenOnPath WashingtonDC Maryland Virginia I495)))
>> I think we are now talking past ourselves.
>>
>> If you have some alternative to RDF that works, just point me to it. I
>> think that's the best use of our respective time at this juncture.
>>
>> Kingsley
>>>
>>> -- doug foxvog
>>> ...
>>>> Kingsley
>>>>> -- doug foxvog
>>>   
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>>
>> -- 
>>
>> Regards,
>>
>> Kingsley Idehen      
>> Founder & CEO
>> OpenLink Software
>> Company Web: http://www.openlinksw.com
>> Personal Weblog: http://www.openlinksw.com/blog/~kidehen
>> Twitter/Identi.ca handle: @kidehen
>> Google+ Profile: https://plus.google.com/112399767740508618350/about
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>>
>>
>>
>>
>>
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>
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--     (021)

Regards,    (022)

Kingsley Idehen 
Founder & CEO
OpenLink Software
Company Web: http://www.openlinksw.com
Personal Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca handle: @kidehen
Google+ Profile: https://plus.google.com/112399767740508618350/about
LinkedIn Profile: http://www.linkedin.com/in/kidehen    (023)

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