Re: Appeal to "database theory" in Direct Mapping

On Jun 22, 2011, at 4:35 AM, Richard Cyganiak wrote:

> Quote from the Direct Mapping:
>
> [[
> Rows in tables with no primary key may still be referenced by  
> foreign keys. (Relational database theory tells us that these rows  
> must be unique as foreign keys reference candidate keys and  
> candidate keys are unique across all the rows in a table.)
> ]]

I agree the parenthetical expression should be eliminated.

>
> I do not like the appeal to database theory. Our normative  
> reference is ISO/IEC-9075-2:2008; if it ever happens to disagree  
> with database theory (it doesn't in this case, but could well  
> elsewhere) then it's the ISO spec that counts. Therefore, I ask  
> that the editors to either change the wording, or to just remove  
> the two sentences because the following sentence is actually  
> perfectly clear on its own:
>
> [[
> References to rows in tables with no primary key are expressed as  
> RDF triples with blank nodes for objects, where that blank node is  
> the same node used for the subject in the referenced row.
> ]]
>
> That's all that really needs to be said.
>
> In that sentence, I'd suggest a further optimization: Replace  
> "References to rows in tables" with "References to tables".

It is the row that is referenced not the table.  Perhaps this issue  
becomes moot if the phrasing is made more active:
[[
Rows referenced in tables created without a primary key are expressed  
as RDF triples with blank nodes for objects, where that blank node is  
the same node used for the subject in the referenced row.

]]

Dan

>
> Best,
> Richard

Received on Wednesday, 22 June 2011 18:32:17 UTC