Re: unhappy responses

On 9 Mar 2009, at 19:26, Alan Ruttenberg wrote:

> I've followed up with Marijke about the issue of hasKey. The issue for
> her is that "key" has a specific meaning in the ER and Conceptual data
> modeling worlds and that the common notion is that keys are
> functional. Because of the overlap of our user base with that one, she
> suggests at least a short note in syntax commenting on the difference
> between our keys and what people will be familiar with, and suggests
> that one of our user facing documents show how to map keys in this
> other sense to our keys (i.e. hasKey + functional properties).

I'm lukewarm trending toward cold. In Jim's case there was an *actual*  
misunderstanding that wasted time. Here there's not. I don't think we  
should do more than we did for Jim's case. "Please note that OWL Keys  
are not functional by default."

> In support of her view she offers two citations:

Oh please.

> "The Entity-Relationship Model-Toward a Unified View of Data",by Peter
> Pin-Shan Chen,

I'm certainly well aware of that paper and teach it regularly. We're  
all, I hope, aware of the common case of relational theory where keys  
are 1-1.

> that she considers a foundational paper in the area,

It is, but foundational papers don't tell us a lot about our audience.

> which says, among other things: "Basically, an entity key is a group
> of attributes such that the mapping from the entity set to the
> corresponding group of value sets is one-to-one."

And in relational theory it's about the uniqueness of a tuple. I'm  
underwhelmed.

It also requires the *presence* of keys. Which we can't enforce.

I suggest we do the minimal possible. While I certainly didn't do  
anything like a comprehensive or random survey, the users I talked to  
when designing EasyKeys didn't care at *all* about functionality, nor  
did they mention it. When I asked specifically about it, they were  
happy at the lack of functionality.

People have pressed for InverseFunctional Data Properties *as keys*.  
"IFDP, aka keys" is a common refrain. IF does not mean F.

So, I'm pretty much back to no change, or, at most, the sentence above.

Cheers,
Bijan.

Received on Monday, 9 March 2009 19:46:08 UTC