- From: Kingsley Idehen <kidehen@openlinksw.com>
- Date: Fri, 24 Aug 2012 14:45:53 -0400
- To: public-rdf-wg@w3.org
- Message-ID: <5037CBE1.10201@openlinksw.com>
On 8/24/12 12:09 PM, Sandro Hawke wrote: > On 08/24/2012 07:32 AM, Kingsley Idehen wrote: >> On 8/24/12 7:10 AM, Sandro Hawke wrote: >>> On 08/24/2012 05:31 AM, Richard Cyganiak wrote: >>>> Sandro, >>>> >>>> On 24 Aug 2012, at 03:53, Sandro Hawke wrote: >>>>> People will need some way linguistically to distinguish X from Y >>>>> People will instinctively say X to clarify they mean Y >>>>> People rarely mean to only be talking about X, and when they do, >>>>> they should put the word Y in there >>>>> People should be able to use X when they want to clarify they're >>>>> talking about Y >>>> That kind of argument is irrelevant. People talk the way they talk. >>>> They won't pay attention to what we write anyways for the most >>>> part. We're not in the business of helping them to express themselves. >>>> >>>> We are in the business of extending an existing technical >>>> specification with clear definitions of a few additional concepts >>>> in order to promote consistency between W3C specifications and to >>>> promote interoperability between implementations that already use >>>> these concepts in some form. >>>> >>>> We'll never get anywhere with this discussion if we entertain the >>>> crazy notion that we can magically solve all uncertainty and >>>> enlighten the RDF community with a Great Global Renaming. >>> >>> That's a strawman. I'm not saying names will magically solve >>> anything. It sounds like our disagreement is a matter of degree. I >>> believe our choice of terms will affect the quality & uptake of our >>> specs by X%, while you believe it is a smaller amount Y%. Perhaps >>> X=30 and Y=10. >>> >>> This is complicated by the fact that names interact with mental >>> models, so sometimes when we're discussing names, I think it turns >>> out to be a proxy for mental models. And as we change our >>> models, our opinions on the best names are likely to change. >>> >>> So, let's put this back in the box for now, and hopefully when we've >>> got the model solved, we can spend one telecon talking over >>> proposals and make a final decision. (I suppose we should give it >>> an ISSUE number, or broaden ISSUE-14 to include this.) >>> >>> I updated http://www.w3.org/2011/rdf-wg/wiki/Graph_Terminology and made >>> http://www.w3.org/2011/rdf-wg/wiki/Graph_Terminology/Options and I'm >>> quite happy to let the matter drop for as long as possible. >>> >>> -- Sandro >> >> Sandro, >> >> How would you map g-box, g-snap, and g-text in formal relational DBMS >> terminology? Such a mapping would help many. Basically, mapping to >> relations, sets of tuples, and notation. >> > > I'm not really fluent in RDBMS theory terminology. I do know the > terminology database app developers use, though, I think -- the kind > of stuff you find in the Oracle or MySQL manuals (talking about > "tables" instead of "relations"). In that terminology, I'd say: > > g-box: table (or view) > g-snap: dump of a table (or view) > g-snap: not something one normally deals with; either: > - a state of a table; or > - a value which is the set of all the rows in a table. > > This is more of an analogy than a real correspondence, since a table > row is not the same thing as an RDF triple, in general. (You could > make a Subject/Property/Value table, but the data typing of the value > wouldn't work right, in general.) > > -- Sandro Sandro, Here is a nice article on Relational Model concepts: http://www.eng.mu.edu/corlissg/150.07f/ch05.html . I still believe that mapping your world view to relational model concepts will aid bringing this matter to rest. Kingsley > >> Kingsley >>> >>>> Best, >>>> Richard >>>> >>>> >>>> On 24 Aug 2012, at 03:53, Sandro Hawke wrote: >>>> >>>>> On 08/23/2012 11:22 AM, Richard Cyganiak wrote: >>>>>> On 23 Aug 2012, at 16:00, Sandro Hawke wrote: >>>>>>>> You proposed to redefine "graph" by splitting it into two >>>>>>>> separate concepts, a mutable and an immutable one. >>>>>>>> >>>>>>>> I propose to instead redefine "named graph" in the same way, by >>>>>>>> splitting it into two separate concepts, a mutable and >>>>>>>> immutable one. >>>>>>> You lost me here, sorry. What's the use case for an immutable >>>>>>> named graph? >>>>>> I guess I should have said "abstract named graph", sorry if that >>>>>> caused confusion. Abstract IRI-graph-pairs. The thing that SPARQL >>>>>> queries operate over. >>>>>> >>>>>>> And it sounds like you're suggesting "mutable named graph" as >>>>>>> the official term for g-box. Is that right? >>>>>> Almost. My definition of "mutable named graph" would be: >>>>>> >>>>>> "A *mutable named graph* is a resource, denoted by an IRI, that >>>>>> has a mutable association with an (abstract, immutable) RDF >>>>>> graph. The RDF graph is also known as the *state* of the mutable >>>>>> named graph." >>>>>> >>>>>> The key points are: >>>>>> >>>>>> 1) we insist that it is a resource, so the kind of thing denoted >>>>>> by IRIs >>>>>> 2) we insist that it is actually denoted by some IRI >>>>>> 3) it essentially has a mutable slot that contains an RDF graph >>>>>> >>>>>> This means it can cover both the terms "RDF space/g-box" and the >>>>>> term "(name, slot) pair" from the diagram in [1]. >>>>>> >>>>>> I repeat my assertion that there is no need to ever talk about >>>>>> unnamed g-boxes. >>>>> Yeah, this makes sense, but it's not my first or second choice in >>>>> naming proposals. Probably wouldn't help to go into why/why not >>>>> at this point. >>>>> >>>>>>>>> I think the key elements are : (1) we stop using "RDF Graph" >>>>>>>>> as the >>>>>>>>> canonical, precise term for a g-snap; >>>>>>>> I disagree; "RDF graph" is a perfectly fine term. >>>>>>> I wish. I can live with it, but I think it's hardly "fine". >>>>>>> People use it wrong all the time; they say "RDF graph" and mean >>>>>>> a mutable and/or distinct set of RDF triples. >>>>>> I think by actually defining proper terms for these other things, >>>>>> and by clarifying that "graph" can mean "any of the above", we >>>>>> make a solid step towards improving the situation. >>>>> I think you're saying "RDF graph"==g-snap; "graph"=g-snap/or/g-box. >>>>> >>>>> I have a problem with this. I think people will need some way >>>>> linguistically to distinguish "graph" in the RDF world from >>>>> "graph" in the wider world, and the natural way to do that is to >>>>> add the modifier, "RDF". So people will instinctively say "RDF >>>>> graph" to clarify they mean "graph" in the RDF sense (not a bar >>>>> chart or something). But with your proposal, they've now >>>>> accidentally changed to talking about g-snaps. >>>>> >>>>> I think people rarely mean to only be talking about g-snaps, and >>>>> when they do, they can/should put the word "abstract" in there. >>>>> I also think the presence or absence of the modifier "RDF" >>>>> shouldn't affect the semantics of the term -- people should be >>>>> able to use it when they want to clarify they're talking about >>>>> RDF, without it otherwise affecting the meaning. >>>>> >>>>> -- Sandro >>>>> >>>>>> Best, >>>>>> Richard >>>>>> >>>>>> [1] http://www.w3.org/2012/08/RDFNG.html#fig1 >>>>>> >>>>>> >>>>>> >>>>>>> I'm not saying we have to solve this problem, or that we can, >>>>>>> but I think it would be helpful if we could and I think this >>>>>>> proposal is our best bet. >>>>>>> >>>>>>> -- Sandro >>>>>>> >>>>>>>> But we can stress that "RDF graph" is an abstract, unnamed, >>>>>>>> immutable graph, and that when we talk about "graphs" in >>>>>>>> general then we may sometimes mean named ones that may or may >>>>>>>> not be mutable. >>>>>>>> >>>>>>>>> (2) we pick terms for g-box and g-snap that convey the idea >>>>>>>>> that they are two different kinds of "graphs"; >>>>>>>> I disagree; I believe that there is never any need to talk >>>>>>>> about *unnamed* g-boxes; all the g-boxes we want to talk about >>>>>>>> are named. Therefore, a term like "mutable named graph" is >>>>>>>> sufficient to say all that needs to be said about g-boxes. >>>>>>>> >>>>>>>>> (3) we use "graph" if/when we don't mind being ambiguous about >>>>>>>>> g-box/g-snap. >>>>>>>> I'd rephrase that: We can use "graph" if/when we don't mind >>>>>>>> being ambiguous about >>>>>>>> g-snap/abstract-named-graph/mutable-named-graph. For example >>>>>>>> when we say, "SPARQL Update can be used to copy data from one >>>>>>>> graph to another". In that case we mean mutable-named-graph. >>>>>>>> >>>>>>>>> On your details.... let me start with: to you, can you have >>>>>>>>> a named >>>>>>>>> graph that's not in a dataset (or graph store)? >>>>>>>> As defined in SPARQL (named graph == IRI-graph-pair), no. >>>>>>>> >>>>>>>> But if we allow a term such as "mutable named graph", then yes. >>>>>>>> A Turtle document on the Web is a "mutable named graph", in >>>>>>>> that sense. It doesn't have to be in any particular dataset. >>>>>>>> Well, it's in the Web, and for me it makes sense to speak of >>>>>>>> the entire web as a "mutable RDF dataset". >>>>>>>> >>>>>>>> Best, >>>>>>>> Richard >>>>>>>> >>>>>>>> >>>>>>>>> I don't usually hear the term used outside SPARQL, so I don't >>>>>>>>> have much of an ear for that usage. >>>>>>>> -- Sandro >>>>>>>> >>>>>>>>> Best, >>>>>>>>> Richard >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> On 22 Aug 2012, at 18:07, Sandro Hawke wrote: >>>>>>>>> >>>>>>>>>> On 08/21/2012 03:33 AM, Andy Seaborne wrote: >>>>>>>>>>> On 20/08/12 16:30, Sandro Hawke wrote: >>>>>>>>>>>> If it wouldn't cause SPARQL too many problems, I'd suggest >>>>>>>>>>>> we should do >>>>>>>>>>>> the same with dataset, and even allow a dataset to be a >>>>>>>>>>>> kind of graph, I >>>>>>>>>>>> think, so that the world at large can use the word term >>>>>>>>>>>> "RDF dataset" >>>>>>>>>>>> for any collection of RDF data (whether or not it's >>>>>>>>>>>> segmented into named >>>>>>>>>>>> graphs). >>>>>>>>>>> That would be problematic. "RDF Dataset" is a specifically >>>>>>>>>>> defined term. "Dataset" we can be loose about (c.f. VoiD) ; >>>>>>>>>>> "RDF Dataset" is stressing the tie to a particular >>>>>>>>>>> definition. You might as well mix properties and triples if >>>>>>>>>>> you're going to mix things of different "shape". >>>>>>>>>> In the telecon, I mentioned on irc the term "bacronym" but >>>>>>>>>> what I meant was "retronym". These are terms like "cow milk" >>>>>>>>>> that arise once some term ("milk") becomes ambiguous (eg >>>>>>>>>> because of soy milk, almond milk, rice milk, etc). See >>>>>>>>>> >>>>>>>>>> I take the "radical proposal" to be the recognition that some >>>>>>>>>> terms are ambiguous and we need to make retronyms to >>>>>>>>>> disambiguate them. >>>>>>>>>> >>>>>>>>>> Here's a revised proposal: >>>>>>>>>> >>>>>>>>>> - We pick terms like "Abstract RDF Graph" (gsnap) and >>>>>>>>>> "Maintained RDF Graph" (gbox) that fit the retronym model. >>>>>>>>>> It makes it easy, when someone says "graph" or "RDF Graph", >>>>>>>>>> to think/ask, "do you mean abstract or maintained?" (I >>>>>>>>>> don't find these terms quite as ontologically comfortable as >>>>>>>>>> g-snap and g-box/space/data-source, because it makes them >>>>>>>>>> both be subclasses of "graph", but I think this approach >>>>>>>>>> works better for the community.) >>>>>>>>>> >>>>>>>>>> - We clarify that in all W3C specs to date, "RDF Graph" >>>>>>>>>> means "Abstract RDF Graph" >>>>>>>>>> >>>>>>>>>> - Going forward, we avoid using the term "RDF Graph", >>>>>>>>>> using either Abstract Graph or Maintained Graph (with or >>>>>>>>>> without "RDF" in there). Or just "graph" when we don't care >>>>>>>>>> which kind. >>>>>>>>>> >>>>>>>>>> I think that much of the confusion around the term "named >>>>>>>>>> graph" comes from a lack of clarity around whether what is >>>>>>>>>> meant is a "named abstract graph" or a "named maintained >>>>>>>>>> graph". I think the latter is much more common; the >>>>>>>>>> difference doesn't manifest in SPARQL 1.0 because it doesn't >>>>>>>>>> consider the idea of data changing. In my mind, this proposal >>>>>>>>>> is our best chance for being able to coherently keep using >>>>>>>>>> the term "named graph", which seems to be very popular. >>>>>>>>>> >>>>>>>>>> BTW, I think we might also want to define "Frozen" graph, >>>>>>>>>> which is a maintained graph in the sense that it exists in a >>>>>>>>>> computer's storage, but which is required to never change. >>>>>>>>>> This is, I think, mostly what PROV wants to use. >>>>>>>>>> >>>>>>>>>> -- Sandro >>>>>>>>>> >>>>> >>>> >>> >>> >>> >>> >> >> > > > -- 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 LinkedIn Profile: http://www.linkedin.com/in/kidehen
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Received on Friday, 24 August 2012 18:44:23 UTC