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Posted to users@jena.apache.org by Marco Neumann <ma...@gmail.com> on 2018/11/22 13:13:42 UTC
Fwd: ✅ Literals as subjects Re: Toward easier RDF: a proposal
are we prepared in Jena for such a move on the RDF syntax?
---------- Forwarded message ---------
From: Tim Berners-Lee <ti...@w3.org>
Date: Thu, Nov 22, 2018 at 1:05 PM
Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
To: David Booth <da...@dbooth.org>
Cc: SW-forum Web <se...@w3.org>, Dan Brickley <da...@google.com>,
Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <ol...@liu.se>,
Axel Polleres <ax...@polleres.net>
On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
7. Literals as subjects. RDF should allow "anyone to say
anything about anything", but RDF does not currently allow
literals as subjects! (One work-around is to use -- you guessed
it -- a blank node, which in turn is asserted to be owl:sameAs
the literal.) This deficiency may seem unimportant relative
to other RDF difficulties, but it is a peculiar anomaly that
may have greater impact than we realize. Imagine an *average*
developer, new to RDF, who unknowingly violates this rule and
is puzzled when it doesn't work. Negative experiences like
that drive people away. Even more insidiously, imagine this
developer tries to CONSTRUCT triples using a SPARQL query,
and some of those triples happen to have literals in the
subject position. Per the SPARQL standard, those triples will
be silently eliminated from the results,[13] which could lead
to silently producing wrong answers from the application --
the worst of all possible bugs.
Agreed.
I thought we had fixed that in some later spec but I guess not.
All code I have written, like cwm and rdflib.js, allows the same things in
subject and object positions. Life is too short for arbitrary unnecessary
asymmetry.
timbl
--
---
Marco Neumann
KONA
Re: JSON & JENA Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by ajs6f <aj...@apache.org>.
> On Nov 30, 2018, at 10:24 AM, Andy Seaborne <an...@apache.org> wrote:
> On 29/11/2018 15:48, ajs6f wrote:
>> I'm not Martynas, so you didn't misname anyone that I saw.
>> JSON-LD can certainly help with this: any time you have JSON, and you wish it were RDF, JSON-LD is there for you!
>
> This is JSON-LD's strong point.
>
> It is weaker for RDF->JSON, or rather you have to work at it.
>
> Getting nice looking JSON out of RDF via JSON-LD is harder than the mere pretty printing we have for Turtle and RDF/XML. It's closer to wanting the output as speific XML schema (something that has come up several times on StackOverflow in the past 2 weeks). The hard part is "nice looking JSON" has a strong component of being in the eye of the beholder once it's past a flat JSON object.
>
> The JSON-LD ecosystem has stuff to help with this but no longer a matter of a simple "model.write".
This is true, partly because JSON is inherently tree-ish and some means must be used to get the arbitrarily-shaped RDF graph into that shape. For that reason the stuff to which Andy refers includes JSON-LD Framing [1] which allows you to control the shape of the JSON and supply default values for properties in the JSON that may or may not be filled in by RDF triples for any given instance.
ajs6f
[1] https://w3c.github.io/json-ld-framing/
Re: JSON & JENA Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by Andy Seaborne <an...@apache.org>.
On 29/11/2018 15:48, ajs6f wrote:
> I'm not Martynas, so you didn't misname anyone that I saw.
>
> JSON-LD can certainly help with this: any time you have JSON, and you wish it were RDF, JSON-LD is there for you!
This is JSON-LD's strong point.
It is weaker for RDF->JSON, or rather you have to work at it.
Getting nice looking JSON out of RDF via JSON-LD is harder than the mere
pretty printing we have for Turtle and RDF/XML. It's closer to wanting
the output as speific XML schema (something that has come up several
times on StackOverflow in the past 2 weeks). The hard part is "nice
looking JSON" has a strong component of being in the eye of the beholder
once it's past a flat JSON object.
The JSON-LD ecosystem has stuff to help with this but no longer a matter
of a simple "model.write".
Andy
> Whether it's the best choice, only you can say. Keep in mind that JSON-LD contexts can take JSON and create triples (or even quads) from properties. That's it. It cannot create triples that aren't translated directly from a property (except for rdf:type triples, which are a bit weird). It cannot transform data values.
>
> You might end up with a two-stage process, in which you first mung your JSON (as JSON) as need be to clean the data, and then apply a context and let Jena read the RDF directly. If the data is already in a form that is close to what you need, the first phase might be short or absent. If the data is wacky, the gains from introducing JSON-LD might be very small.
>
> ajs6f
>
>> On Nov 29, 2018, at 8:27 AM, Marco Neumann <ma...@gmail.com> wrote:
>>
>> good to know that we are on the same page here Adam. With regards to json
>> let's limit the scope of the discussion here to the Jena project for now. I
>> am not looking at an alternative to JSON-LD, correct my if I am wrong but
>> as far as my limited understanding of JSON-LD goes it is a way to
>> store/serialize RDF like data in a json format. while my use case would be
>> a customer that presents any data in json and wants me to read this into a
>> sparql endpoint for further inspection (with bnodes for arrays, warts and
>> all). Currently I have to programmatically write transformations to allow
>> me to read the data into a Jena store. Can JSON-LD already help me with
>> this task?
>>
>>
>>
>> On Thu, Nov 29, 2018 at 12:47 PM ajs6f <aj...@apache.org> wrote:
>>
>>> I agree _very heartily_ with the caution that Andy and Marco are
>>> expressing. I've been following the conversation on semantic-web@w3.org
>>> and I have yet to hear anything that seems very useful or practical to me.
>>>
>>> That having been said, and speaking very much as a member of W3C's JSON-LD
>>> Working Group, I'm also not ecstatic about setting up an alternative to
>>> JSON-LD. Perhaps you could say a little about why it's not a good choice
>>> for data access? I would hope that you would be able to equip your generic
>>> JSON with a JSON-LD context and roll on without any special new Jena
>>> tooling needed... is that not possible (or optimal) for some reason? If
>>> it's related to Jena, we can talk about it here, and if it's related to
>>> JSON-LD, I'd be very happy to take your concern to the WG.
>>>
>>> ajs6f
>>>
>>>> On Nov 29, 2018, at 7:40 AM, Marco Neumann <ma...@gmail.com>
>>> wrote:
>>>>
>>>> I agree Andy, there is no need to rush things here and break the API.
>>> Maybe
>>>> we could provide an in memory model for "Generalized RDF" as sandbox for
>>>> people to play with. But what I'd like to see are more bridges to the
>>> json
>>>> community as it has become the defacto lingua franca for data exchange on
>>>> the web now.
>>>>
>>>> In particular with regards to generic json rather than json-ld. possibly
>>> a
>>>> generic mapping to a json dataset assembler could work for data access
>>> and
>>>> transformation. has anybody done anything here already?
>>>>
>>>>
>>>> On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org> wrote:
>>>>
>>>>> Internally, that means Graph/Node/Triple and the ARQ engine, Jena really
>>>>> works on what is called "Generalized RDF" in RDF 1.1 - so literals as
>>>>> subjects, literals as predicates blank nodes as predicates - work just
>>>>> fine. Whether they are a good idea is a different question.
>>>>>
>>>>> RDF* works as well (in-memory graphs). Jena has Node_Triple and
>>>>> Node_Graph nowadays for completeness.
>>>>>
>>>>> If we get into structured values (lists not encoded in triples,
>>>>> sets/bags as datastructures - and these are things property graphs and
>>>>> traditionally SQL also find it hard to handle), there would be work to
>>>>> do, but it's not impossible.
>>>>>
>>>>> The impact is on the Model API is where the impact is.
>>>>>
>>>>> Personal opinion about changing the core specs:
>>>>>
>>>>> Being "better"isn't enough. There is lots of investment in people's
>>>>> time and energy has gone in to learning about RDF and communicating
>>>>> about RDF.
>>>>>
>>>>> The impact is when new data meets old apps but also existing
>>>>> thinking/learning/blogs/books/...
>>>>>
>>>>> Changes to the basics need to meet a higher barrier than "better".
>>>>>
>>>>> Andy
>>>>>
>>>>> On 22/11/2018 13:13, Marco Neumann wrote:
>>>>>> are we prepared in Jena for such a move on the RDF syntax?
>>>>>>
>>>>>>
>>>>>>
>>>>>> ---------- Forwarded message ---------
>>>>>> From: Tim Berners-Lee <ti...@w3.org>
>>>>>> Date: Thu, Nov 22, 2018 at 1:05 PM
>>>>>> Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
>>>>>> To: David Booth <da...@dbooth.org>
>>>>>> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <
>>> danbri@google.com
>>>>>> ,
>>>>>> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <olaf.hartig@liu.se
>>>> ,
>>>>>> Axel Polleres <ax...@polleres.net>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
>>>>>>
>>>>>> 7. Literals as subjects. RDF should allow "anyone to say
>>>>>> anything about anything", but RDF does not currently allow
>>>>>> literals as subjects! (One work-around is to use -- you guessed
>>>>>> it -- a blank node, which in turn is asserted to be owl:sameAs
>>>>>> the literal.) This deficiency may seem unimportant relative
>>>>>> to other RDF difficulties, but it is a peculiar anomaly that
>>>>>> may have greater impact than we realize. Imagine an *average*
>>>>>> developer, new to RDF, who unknowingly violates this rule and
>>>>>> is puzzled when it doesn't work. Negative experiences like
>>>>>> that drive people away. Even more insidiously, imagine this
>>>>>> developer tries to CONSTRUCT triples using a SPARQL query,
>>>>>> and some of those triples happen to have literals in the
>>>>>> subject position. Per the SPARQL standard, those triples will
>>>>>> be silently eliminated from the results,[13] which could lead
>>>>>> to silently producing wrong answers from the application --
>>>>>> the worst of all possible bugs.
>>>>>>
>>>>>>
>>>>>> Agreed.
>>>>>>
>>>>>> I thought we had fixed that in some later spec but I guess not.
>>>>>>
>>>>>> All code I have written, like cwm and rdflib.js, allows the same things
>>>>> in
>>>>>> subject and object positions. Life is too short for arbitrary
>>>>> unnecessary
>>>>>> asymmetry.
>>>>>>
>>>>>> timbl
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>>
>>>>
>>>> ---
>>>> Marco Neumann
>>>> KONA
>>>
>>>
>>
>> --
>>
>>
>> ---
>> Marco Neumann
>> KONA
>
Re: JSON & JENA Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by Marco Neumann <ma...@gmail.com>.
Ok so, I was able to look at this in more detail and indeed JSON-LD seems
to be the way to go here. I even found some code from an EU project that
actually builds a whole pipeline around the ETL process that already works.
LinkedPipes ETL quite interesting.
https://etl.linkedpipes.com/tutorials/how-to/map_json_to_rdf
On Thu, Nov 29, 2018 at 3:54 PM ajs6f <aj...@apache.org> wrote:
> I'm not Martynas, so you didn't misname anyone that I saw.
>
> JSON-LD can certainly help with this: any time you have JSON, and you wish
> it were RDF, JSON-LD is there for you! Whether it's the best choice, only
> you can say. Keep in mind that JSON-LD contexts can take JSON and create
> triples (or even quads) from properties. That's it. It cannot create
> triples that aren't translated directly from a property (except for
> rdf:type triples, which are a bit weird). It cannot transform data values.
>
> You might end up with a two-stage process, in which you first mung your
> JSON (as JSON) as need be to clean the data, and then apply a context and
> let Jena read the RDF directly. If the data is already in a form that is
> close to what you need, the first phase might be short or absent. If the
> data is wacky, the gains from introducing JSON-LD might be very small.
>
> ajs6f
>
> > On Nov 29, 2018, at 8:27 AM, Marco Neumann <ma...@gmail.com>
> wrote:
> >
> > good to know that we are on the same page here Adam. With regards to json
> > let's limit the scope of the discussion here to the Jena project for
> now. I
> > am not looking at an alternative to JSON-LD, correct my if I am wrong but
> > as far as my limited understanding of JSON-LD goes it is a way to
> > store/serialize RDF like data in a json format. while my use case would
> be
> > a customer that presents any data in json and wants me to read this into
> a
> > sparql endpoint for further inspection (with bnodes for arrays, warts and
> > all). Currently I have to programmatically write transformations to allow
> > me to read the data into a Jena store. Can JSON-LD already help me with
> > this task?
> >
> >
> >
> > On Thu, Nov 29, 2018 at 12:47 PM ajs6f <aj...@apache.org> wrote:
> >
> >> I agree _very heartily_ with the caution that Andy and Marco are
> >> expressing. I've been following the conversation on semantic-web@w3.org
> >> and I have yet to hear anything that seems very useful or practical to
> me.
> >>
> >> That having been said, and speaking very much as a member of W3C's
> JSON-LD
> >> Working Group, I'm also not ecstatic about setting up an alternative to
> >> JSON-LD. Perhaps you could say a little about why it's not a good choice
> >> for data access? I would hope that you would be able to equip your
> generic
> >> JSON with a JSON-LD context and roll on without any special new Jena
> >> tooling needed... is that not possible (or optimal) for some reason? If
> >> it's related to Jena, we can talk about it here, and if it's related to
> >> JSON-LD, I'd be very happy to take your concern to the WG.
> >>
> >> ajs6f
> >>
> >>> On Nov 29, 2018, at 7:40 AM, Marco Neumann <ma...@gmail.com>
> >> wrote:
> >>>
> >>> I agree Andy, there is no need to rush things here and break the API.
> >> Maybe
> >>> we could provide an in memory model for "Generalized RDF" as sandbox
> for
> >>> people to play with. But what I'd like to see are more bridges to the
> >> json
> >>> community as it has become the defacto lingua franca for data exchange
> on
> >>> the web now.
> >>>
> >>> In particular with regards to generic json rather than json-ld.
> possibly
> >> a
> >>> generic mapping to a json dataset assembler could work for data access
> >> and
> >>> transformation. has anybody done anything here already?
> >>>
> >>>
> >>> On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org> wrote:
> >>>
> >>>> Internally, that means Graph/Node/Triple and the ARQ engine, Jena
> really
> >>>> works on what is called "Generalized RDF" in RDF 1.1 - so literals as
> >>>> subjects, literals as predicates blank nodes as predicates - work just
> >>>> fine. Whether they are a good idea is a different question.
> >>>>
> >>>> RDF* works as well (in-memory graphs). Jena has Node_Triple and
> >>>> Node_Graph nowadays for completeness.
> >>>>
> >>>> If we get into structured values (lists not encoded in triples,
> >>>> sets/bags as datastructures - and these are things property graphs and
> >>>> traditionally SQL also find it hard to handle), there would be work to
> >>>> do, but it's not impossible.
> >>>>
> >>>> The impact is on the Model API is where the impact is.
> >>>>
> >>>> Personal opinion about changing the core specs:
> >>>>
> >>>> Being "better"isn't enough. There is lots of investment in people's
> >>>> time and energy has gone in to learning about RDF and communicating
> >>>> about RDF.
> >>>>
> >>>> The impact is when new data meets old apps but also existing
> >>>> thinking/learning/blogs/books/...
> >>>>
> >>>> Changes to the basics need to meet a higher barrier than "better".
> >>>>
> >>>> Andy
> >>>>
> >>>> On 22/11/2018 13:13, Marco Neumann wrote:
> >>>>> are we prepared in Jena for such a move on the RDF syntax?
> >>>>>
> >>>>>
> >>>>>
> >>>>> ---------- Forwarded message ---------
> >>>>> From: Tim Berners-Lee <ti...@w3.org>
> >>>>> Date: Thu, Nov 22, 2018 at 1:05 PM
> >>>>> Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
> >>>>> To: David Booth <da...@dbooth.org>
> >>>>> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <
> >> danbri@google.com
> >>>>> ,
> >>>>> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <
> olaf.hartig@liu.se
> >>> ,
> >>>>> Axel Polleres <ax...@polleres.net>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
> >>>>>
> >>>>> 7. Literals as subjects. RDF should allow "anyone to say
> >>>>> anything about anything", but RDF does not currently allow
> >>>>> literals as subjects! (One work-around is to use -- you guessed
> >>>>> it -- a blank node, which in turn is asserted to be owl:sameAs
> >>>>> the literal.) This deficiency may seem unimportant relative
> >>>>> to other RDF difficulties, but it is a peculiar anomaly that
> >>>>> may have greater impact than we realize. Imagine an *average*
> >>>>> developer, new to RDF, who unknowingly violates this rule and
> >>>>> is puzzled when it doesn't work. Negative experiences like
> >>>>> that drive people away. Even more insidiously, imagine this
> >>>>> developer tries to CONSTRUCT triples using a SPARQL query,
> >>>>> and some of those triples happen to have literals in the
> >>>>> subject position. Per the SPARQL standard, those triples will
> >>>>> be silently eliminated from the results,[13] which could lead
> >>>>> to silently producing wrong answers from the application --
> >>>>> the worst of all possible bugs.
> >>>>>
> >>>>>
> >>>>> Agreed.
> >>>>>
> >>>>> I thought we had fixed that in some later spec but I guess not.
> >>>>>
> >>>>> All code I have written, like cwm and rdflib.js, allows the same
> things
> >>>> in
> >>>>> subject and object positions. Life is too short for arbitrary
> >>>> unnecessary
> >>>>> asymmetry.
> >>>>>
> >>>>> timbl
> >>>>>
> >>>>>
> >>>>>
> >>>>
> >>>
> >>>
> >>> --
> >>>
> >>>
> >>> ---
> >>> Marco Neumann
> >>> KONA
> >>
> >>
> >
> > --
> >
> >
> > ---
> > Marco Neumann
> > KONA
>
>
--
---
Marco Neumann
KONA
Re: JSON & JENA Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by Marco Neumann <ma...@gmail.com>.
Ok so I will give it a spin over the weekend to see how it performs and if
it gets me what I want
On Thu 29 Nov 2018 at 15:54, ajs6f <aj...@apache.org> wrote:
> I'm not Martynas, so you didn't misname anyone that I saw.
>
> JSON-LD can certainly help with this: any time you have JSON, and you wish
> it were RDF, JSON-LD is there for you! Whether it's the best choice, only
> you can say. Keep in mind that JSON-LD contexts can take JSON and create
> triples (or even quads) from properties. That's it. It cannot create
> triples that aren't translated directly from a property (except for
> rdf:type triples, which are a bit weird). It cannot transform data values.
>
> You might end up with a two-stage process, in which you first mung your
> JSON (as JSON) as need be to clean the data, and then apply a context and
> let Jena read the RDF directly. If the data is already in a form that is
> close to what you need, the first phase might be short or absent. If the
> data is wacky, the gains from introducing JSON-LD might be very small.
>
> ajs6f
>
> > On Nov 29, 2018, at 8:27 AM, Marco Neumann <ma...@gmail.com>
> wrote:
> >
> > good to know that we are on the same page here Adam. With regards to json
> > let's limit the scope of the discussion here to the Jena project for
> now. I
> > am not looking at an alternative to JSON-LD, correct my if I am wrong but
> > as far as my limited understanding of JSON-LD goes it is a way to
> > store/serialize RDF like data in a json format. while my use case would
> be
> > a customer that presents any data in json and wants me to read this into
> a
> > sparql endpoint for further inspection (with bnodes for arrays, warts and
> > all). Currently I have to programmatically write transformations to allow
> > me to read the data into a Jena store. Can JSON-LD already help me with
> > this task?
> >
> >
> >
> > On Thu, Nov 29, 2018 at 12:47 PM ajs6f <aj...@apache.org> wrote:
> >
> >> I agree _very heartily_ with the caution that Andy and Marco are
> >> expressing. I've been following the conversation on semantic-web@w3.org
> >> and I have yet to hear anything that seems very useful or practical to
> me.
> >>
> >> That having been said, and speaking very much as a member of W3C's
> JSON-LD
> >> Working Group, I'm also not ecstatic about setting up an alternative to
> >> JSON-LD. Perhaps you could say a little about why it's not a good choice
> >> for data access? I would hope that you would be able to equip your
> generic
> >> JSON with a JSON-LD context and roll on without any special new Jena
> >> tooling needed... is that not possible (or optimal) for some reason? If
> >> it's related to Jena, we can talk about it here, and if it's related to
> >> JSON-LD, I'd be very happy to take your concern to the WG.
> >>
> >> ajs6f
> >>
> >>> On Nov 29, 2018, at 7:40 AM, Marco Neumann <ma...@gmail.com>
> >> wrote:
> >>>
> >>> I agree Andy, there is no need to rush things here and break the API.
> >> Maybe
> >>> we could provide an in memory model for "Generalized RDF" as sandbox
> for
> >>> people to play with. But what I'd like to see are more bridges to the
> >> json
> >>> community as it has become the defacto lingua franca for data exchange
> on
> >>> the web now.
> >>>
> >>> In particular with regards to generic json rather than json-ld.
> possibly
> >> a
> >>> generic mapping to a json dataset assembler could work for data access
> >> and
> >>> transformation. has anybody done anything here already?
> >>>
> >>>
> >>> On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org> wrote:
> >>>
> >>>> Internally, that means Graph/Node/Triple and the ARQ engine, Jena
> really
> >>>> works on what is called "Generalized RDF" in RDF 1.1 - so literals as
> >>>> subjects, literals as predicates blank nodes as predicates - work just
> >>>> fine. Whether they are a good idea is a different question.
> >>>>
> >>>> RDF* works as well (in-memory graphs). Jena has Node_Triple and
> >>>> Node_Graph nowadays for completeness.
> >>>>
> >>>> If we get into structured values (lists not encoded in triples,
> >>>> sets/bags as datastructures - and these are things property graphs and
> >>>> traditionally SQL also find it hard to handle), there would be work to
> >>>> do, but it's not impossible.
> >>>>
> >>>> The impact is on the Model API is where the impact is.
> >>>>
> >>>> Personal opinion about changing the core specs:
> >>>>
> >>>> Being "better"isn't enough. There is lots of investment in people's
> >>>> time and energy has gone in to learning about RDF and communicating
> >>>> about RDF.
> >>>>
> >>>> The impact is when new data meets old apps but also existing
> >>>> thinking/learning/blogs/books/...
> >>>>
> >>>> Changes to the basics need to meet a higher barrier than "better".
> >>>>
> >>>> Andy
> >>>>
> >>>> On 22/11/2018 13:13, Marco Neumann wrote:
> >>>>> are we prepared in Jena for such a move on the RDF syntax?
> >>>>>
> >>>>>
> >>>>>
> >>>>> ---------- Forwarded message ---------
> >>>>> From: Tim Berners-Lee <ti...@w3.org>
> >>>>> Date: Thu, Nov 22, 2018 at 1:05 PM
> >>>>> Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
> >>>>> To: David Booth <da...@dbooth.org>
> >>>>> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <
> >> danbri@google.com
> >>>>> ,
> >>>>> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <
> olaf.hartig@liu.se
> >>> ,
> >>>>> Axel Polleres <ax...@polleres.net>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
> >>>>>
> >>>>> 7. Literals as subjects. RDF should allow "anyone to say
> >>>>> anything about anything", but RDF does not currently allow
> >>>>> literals as subjects! (One work-around is to use -- you guessed
> >>>>> it -- a blank node, which in turn is asserted to be owl:sameAs
> >>>>> the literal.) This deficiency may seem unimportant relative
> >>>>> to other RDF difficulties, but it is a peculiar anomaly that
> >>>>> may have greater impact than we realize. Imagine an *average*
> >>>>> developer, new to RDF, who unknowingly violates this rule and
> >>>>> is puzzled when it doesn't work. Negative experiences like
> >>>>> that drive people away. Even more insidiously, imagine this
> >>>>> developer tries to CONSTRUCT triples using a SPARQL query,
> >>>>> and some of those triples happen to have literals in the
> >>>>> subject position. Per the SPARQL standard, those triples will
> >>>>> be silently eliminated from the results,[13] which could lead
> >>>>> to silently producing wrong answers from the application --
> >>>>> the worst of all possible bugs.
> >>>>>
> >>>>>
> >>>>> Agreed.
> >>>>>
> >>>>> I thought we had fixed that in some later spec but I guess not.
> >>>>>
> >>>>> All code I have written, like cwm and rdflib.js, allows the same
> things
> >>>> in
> >>>>> subject and object positions. Life is too short for arbitrary
> >>>> unnecessary
> >>>>> asymmetry.
> >>>>>
> >>>>> timbl
> >>>>>
> >>>>>
> >>>>>
> >>>>
> >>>
> >>>
> >>> --
> >>>
> >>>
> >>> ---
> >>> Marco Neumann
> >>> KONA
> >>
> >>
> >
> > --
> >
> >
> > ---
> > Marco Neumann
> > KONA
>
> --
---
Marco Neumann
KONA
Re: JSON & JENA Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by ajs6f <aj...@apache.org>.
I'm not Martynas, so you didn't misname anyone that I saw.
JSON-LD can certainly help with this: any time you have JSON, and you wish it were RDF, JSON-LD is there for you! Whether it's the best choice, only you can say. Keep in mind that JSON-LD contexts can take JSON and create triples (or even quads) from properties. That's it. It cannot create triples that aren't translated directly from a property (except for rdf:type triples, which are a bit weird). It cannot transform data values.
You might end up with a two-stage process, in which you first mung your JSON (as JSON) as need be to clean the data, and then apply a context and let Jena read the RDF directly. If the data is already in a form that is close to what you need, the first phase might be short or absent. If the data is wacky, the gains from introducing JSON-LD might be very small.
ajs6f
> On Nov 29, 2018, at 8:27 AM, Marco Neumann <ma...@gmail.com> wrote:
>
> good to know that we are on the same page here Adam. With regards to json
> let's limit the scope of the discussion here to the Jena project for now. I
> am not looking at an alternative to JSON-LD, correct my if I am wrong but
> as far as my limited understanding of JSON-LD goes it is a way to
> store/serialize RDF like data in a json format. while my use case would be
> a customer that presents any data in json and wants me to read this into a
> sparql endpoint for further inspection (with bnodes for arrays, warts and
> all). Currently I have to programmatically write transformations to allow
> me to read the data into a Jena store. Can JSON-LD already help me with
> this task?
>
>
>
> On Thu, Nov 29, 2018 at 12:47 PM ajs6f <aj...@apache.org> wrote:
>
>> I agree _very heartily_ with the caution that Andy and Marco are
>> expressing. I've been following the conversation on semantic-web@w3.org
>> and I have yet to hear anything that seems very useful or practical to me.
>>
>> That having been said, and speaking very much as a member of W3C's JSON-LD
>> Working Group, I'm also not ecstatic about setting up an alternative to
>> JSON-LD. Perhaps you could say a little about why it's not a good choice
>> for data access? I would hope that you would be able to equip your generic
>> JSON with a JSON-LD context and roll on without any special new Jena
>> tooling needed... is that not possible (or optimal) for some reason? If
>> it's related to Jena, we can talk about it here, and if it's related to
>> JSON-LD, I'd be very happy to take your concern to the WG.
>>
>> ajs6f
>>
>>> On Nov 29, 2018, at 7:40 AM, Marco Neumann <ma...@gmail.com>
>> wrote:
>>>
>>> I agree Andy, there is no need to rush things here and break the API.
>> Maybe
>>> we could provide an in memory model for "Generalized RDF" as sandbox for
>>> people to play with. But what I'd like to see are more bridges to the
>> json
>>> community as it has become the defacto lingua franca for data exchange on
>>> the web now.
>>>
>>> In particular with regards to generic json rather than json-ld. possibly
>> a
>>> generic mapping to a json dataset assembler could work for data access
>> and
>>> transformation. has anybody done anything here already?
>>>
>>>
>>> On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org> wrote:
>>>
>>>> Internally, that means Graph/Node/Triple and the ARQ engine, Jena really
>>>> works on what is called "Generalized RDF" in RDF 1.1 - so literals as
>>>> subjects, literals as predicates blank nodes as predicates - work just
>>>> fine. Whether they are a good idea is a different question.
>>>>
>>>> RDF* works as well (in-memory graphs). Jena has Node_Triple and
>>>> Node_Graph nowadays for completeness.
>>>>
>>>> If we get into structured values (lists not encoded in triples,
>>>> sets/bags as datastructures - and these are things property graphs and
>>>> traditionally SQL also find it hard to handle), there would be work to
>>>> do, but it's not impossible.
>>>>
>>>> The impact is on the Model API is where the impact is.
>>>>
>>>> Personal opinion about changing the core specs:
>>>>
>>>> Being "better"isn't enough. There is lots of investment in people's
>>>> time and energy has gone in to learning about RDF and communicating
>>>> about RDF.
>>>>
>>>> The impact is when new data meets old apps but also existing
>>>> thinking/learning/blogs/books/...
>>>>
>>>> Changes to the basics need to meet a higher barrier than "better".
>>>>
>>>> Andy
>>>>
>>>> On 22/11/2018 13:13, Marco Neumann wrote:
>>>>> are we prepared in Jena for such a move on the RDF syntax?
>>>>>
>>>>>
>>>>>
>>>>> ---------- Forwarded message ---------
>>>>> From: Tim Berners-Lee <ti...@w3.org>
>>>>> Date: Thu, Nov 22, 2018 at 1:05 PM
>>>>> Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
>>>>> To: David Booth <da...@dbooth.org>
>>>>> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <
>> danbri@google.com
>>>>> ,
>>>>> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <olaf.hartig@liu.se
>>> ,
>>>>> Axel Polleres <ax...@polleres.net>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
>>>>>
>>>>> 7. Literals as subjects. RDF should allow "anyone to say
>>>>> anything about anything", but RDF does not currently allow
>>>>> literals as subjects! (One work-around is to use -- you guessed
>>>>> it -- a blank node, which in turn is asserted to be owl:sameAs
>>>>> the literal.) This deficiency may seem unimportant relative
>>>>> to other RDF difficulties, but it is a peculiar anomaly that
>>>>> may have greater impact than we realize. Imagine an *average*
>>>>> developer, new to RDF, who unknowingly violates this rule and
>>>>> is puzzled when it doesn't work. Negative experiences like
>>>>> that drive people away. Even more insidiously, imagine this
>>>>> developer tries to CONSTRUCT triples using a SPARQL query,
>>>>> and some of those triples happen to have literals in the
>>>>> subject position. Per the SPARQL standard, those triples will
>>>>> be silently eliminated from the results,[13] which could lead
>>>>> to silently producing wrong answers from the application --
>>>>> the worst of all possible bugs.
>>>>>
>>>>>
>>>>> Agreed.
>>>>>
>>>>> I thought we had fixed that in some later spec but I guess not.
>>>>>
>>>>> All code I have written, like cwm and rdflib.js, allows the same things
>>>> in
>>>>> subject and object positions. Life is too short for arbitrary
>>>> unnecessary
>>>>> asymmetry.
>>>>>
>>>>> timbl
>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>> --
>>>
>>>
>>> ---
>>> Marco Neumann
>>> KONA
>>
>>
>
> --
>
>
> ---
> Marco Neumann
> KONA
Re: JSON & JENA Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by Marco Neumann <ma...@gmail.com>.
I've used xslt transformations in the past and was impressed by the speed
and its ability to transform large documents. But in the end I usually
reverted back to custom transformations (in code) on the production machine
due to quirks in the incoming or outgoing data. Still a generic JSON to RDF
template might be a god guidance for future development. As mention earlier
I will take a look at the JSON-LD tools to see if we already have something
in place here.
On Thu 29 Nov 2018 at 15:58, Martynas Jusevičius <ma...@atomgraph.com>
wrote:
> Sure, but you get that if you produce RDF/XML or TriX. I've tried that
> and transformed JSON directly into TriX with Saxon.
> On Thu, Nov 29, 2018 at 4:41 PM Marco Neumann <ma...@gmail.com>
> wrote:
> >
> > thanks for the link Martynas, one still has to go to rdf from xml. I find
> > the data assembler in jena/d2rq more convenient but am open to new ideas.
> >
> > btw I never quite know who is posting on ajs6f hence the misnomer
> >
> > On Thu 29. Nov 2018 at 14:29, Martynas Jusevičius <
> martynas@atomgraph.com>
> > wrote:
> >
> > > Marco,
> > >
> > > FYI XSLT 3.0 supports JSON transformations:
> > > https://www.w3.org/TR/xslt-30/#json
> > >
> > > Martynas
> > > On Thu, Nov 29, 2018 at 2:27 PM Marco Neumann <marco.neumann@gmail.com
> >
> > > wrote:
> > > >
> > > > good to know that we are on the same page here Adam. With regards to
> json
> > > > let's limit the scope of the discussion here to the Jena project for
> > > now. I
> > > > am not looking at an alternative to JSON-LD, correct my if I am
> wrong but
> > > > as far as my limited understanding of JSON-LD goes it is a way to
> > > > store/serialize RDF like data in a json format. while my use case
> would
> > > be
> > > > a customer that presents any data in json and wants me to read this
> into
> > > a
> > > > sparql endpoint for further inspection (with bnodes for arrays,
> warts and
> > > > all). Currently I have to programmatically write transformations to
> allow
> > > > me to read the data into a Jena store. Can JSON-LD already help me
> with
> > > > this task?
> > > >
> > > >
> > > >
> > > > On Thu, Nov 29, 2018 at 12:47 PM ajs6f <aj...@apache.org> wrote:
> > > >
> > > > > I agree _very heartily_ with the caution that Andy and Marco are
> > > > > expressing. I've been following the conversation on
> > > semantic-web@w3.org
> > > > > and I have yet to hear anything that seems very useful or
> practical to
> > > me.
> > > > >
> > > > > That having been said, and speaking very much as a member of W3C's
> > > JSON-LD
> > > > > Working Group, I'm also not ecstatic about setting up an
> alternative to
> > > > > JSON-LD. Perhaps you could say a little about why it's not a good
> > > choice
> > > > > for data access? I would hope that you would be able to equip your
> > > generic
> > > > > JSON with a JSON-LD context and roll on without any special new
> Jena
> > > > > tooling needed... is that not possible (or optimal) for some
> reason? If
> > > > > it's related to Jena, we can talk about it here, and if it's
> related to
> > > > > JSON-LD, I'd be very happy to take your concern to the WG.
> > > > >
> > > > > ajs6f
> > > > >
> > > > > > On Nov 29, 2018, at 7:40 AM, Marco Neumann <
> marco.neumann@gmail.com>
> > > > > wrote:
> > > > > >
> > > > > > I agree Andy, there is no need to rush things here and break the
> API.
> > > > > Maybe
> > > > > > we could provide an in memory model for "Generalized RDF" as
> sandbox
> > > for
> > > > > > people to play with. But what I'd like to see are more bridges
> to the
> > > > > json
> > > > > > community as it has become the defacto lingua franca for data
> > > exchange on
> > > > > > the web now.
> > > > > >
> > > > > > In particular with regards to generic json rather than json-ld.
> > > possibly
> > > > > a
> > > > > > generic mapping to a json dataset assembler could work for data
> > > access
> > > > > and
> > > > > > transformation. has anybody done anything here already?
> > > > > >
> > > > > >
> > > > > > On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org>
> > > wrote:
> > > > > >
> > > > > >> Internally, that means Graph/Node/Triple and the ARQ engine,
> Jena
> > > really
> > > > > >> works on what is called "Generalized RDF" in RDF 1.1 - so
> literals
> > > as
> > > > > >> subjects, literals as predicates blank nodes as predicates -
> work
> > > just
> > > > > >> fine. Whether they are a good idea is a different question.
> > > > > >>
> > > > > >> RDF* works as well (in-memory graphs). Jena has Node_Triple and
> > > > > >> Node_Graph nowadays for completeness.
> > > > > >>
> > > > > >> If we get into structured values (lists not encoded in triples,
> > > > > >> sets/bags as datastructures - and these are things property
> graphs
> > > and
> > > > > >> traditionally SQL also find it hard to handle), there would be
> work
> > > to
> > > > > >> do, but it's not impossible.
> > > > > >>
> > > > > >> The impact is on the Model API is where the impact is.
> > > > > >>
> > > > > >> Personal opinion about changing the core specs:
> > > > > >>
> > > > > >> Being "better"isn't enough. There is lots of investment in
> people's
> > > > > >> time and energy has gone in to learning about RDF and
> communicating
> > > > > >> about RDF.
> > > > > >>
> > > > > >> The impact is when new data meets old apps but also existing
> > > > > >> thinking/learning/blogs/books/...
> > > > > >>
> > > > > >> Changes to the basics need to meet a higher barrier than
> "better".
> > > > > >>
> > > > > >> Andy
> > > > > >>
> > > > > >> On 22/11/2018 13:13, Marco Neumann wrote:
> > > > > >>> are we prepared in Jena for such a move on the RDF syntax?
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> ---------- Forwarded message ---------
> > > > > >>> From: Tim Berners-Lee <ti...@w3.org>
> > > > > >>> Date: Thu, Nov 22, 2018 at 1:05 PM
> > > > > >>> Subject: ✅ Literals as subjects Re: Toward easier RDF: a
> proposal
> > > > > >>> To: David Booth <da...@dbooth.org>
> > > > > >>> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <
> > > > > danbri@google.com
> > > > > >>> ,
> > > > > >>> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <
> > > olaf.hartig@liu.se
> > > > > >,
> > > > > >>> Axel Polleres <ax...@polleres.net>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org>
> wrote:
> > > > > >>>
> > > > > >>> 7. Literals as subjects. RDF should allow "anyone to say
> > > > > >>> anything about anything", but RDF does not currently allow
> > > > > >>> literals as subjects! (One work-around is to use -- you
> guessed
> > > > > >>> it -- a blank node, which in turn is asserted to be owl:sameAs
> > > > > >>> the literal.) This deficiency may seem unimportant relative
> > > > > >>> to other RDF difficulties, but it is a peculiar anomaly that
> > > > > >>> may have greater impact than we realize. Imagine an *average*
> > > > > >>> developer, new to RDF, who unknowingly violates this rule and
> > > > > >>> is puzzled when it doesn't work. Negative experiences like
> > > > > >>> that drive people away. Even more insidiously, imagine this
> > > > > >>> developer tries to CONSTRUCT triples using a SPARQL query,
> > > > > >>> and some of those triples happen to have literals in the
> > > > > >>> subject position. Per the SPARQL standard, those triples will
> > > > > >>> be silently eliminated from the results,[13] which could lead
> > > > > >>> to silently producing wrong answers from the application --
> > > > > >>> the worst of all possible bugs.
> > > > > >>>
> > > > > >>>
> > > > > >>> Agreed.
> > > > > >>>
> > > > > >>> I thought we had fixed that in some later spec but I guess not.
> > > > > >>>
> > > > > >>> All code I have written, like cwm and rdflib.js, allows the
> same
> > > things
> > > > > >> in
> > > > > >>> subject and object positions. Life is too short for arbitrary
> > > > > >> unnecessary
> > > > > >>> asymmetry.
> > > > > >>>
> > > > > >>> timbl
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>
> > > > > >
> > > > > >
> > > > > > --
> > > > > >
> > > > > >
> > > > > > ---
> > > > > > Marco Neumann
> > > > > > KONA
> > > > >
> > > > >
> > > >
> > > > --
> > > >
> > > >
> > > > ---
> > > > Marco Neumann
> > > > KONA
> > >
> > --
> >
> >
> > ---
> > Marco Neumann
> > KONA
>
--
---
Marco Neumann
KONA
Re: JSON & JENA Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by Martynas Jusevičius <ma...@atomgraph.com>.
Sure, but you get that if you produce RDF/XML or TriX. I've tried that
and transformed JSON directly into TriX with Saxon.
On Thu, Nov 29, 2018 at 4:41 PM Marco Neumann <ma...@gmail.com> wrote:
>
> thanks for the link Martynas, one still has to go to rdf from xml. I find
> the data assembler in jena/d2rq more convenient but am open to new ideas.
>
> btw I never quite know who is posting on ajs6f hence the misnomer
>
> On Thu 29. Nov 2018 at 14:29, Martynas Jusevičius <ma...@atomgraph.com>
> wrote:
>
> > Marco,
> >
> > FYI XSLT 3.0 supports JSON transformations:
> > https://www.w3.org/TR/xslt-30/#json
> >
> > Martynas
> > On Thu, Nov 29, 2018 at 2:27 PM Marco Neumann <ma...@gmail.com>
> > wrote:
> > >
> > > good to know that we are on the same page here Adam. With regards to json
> > > let's limit the scope of the discussion here to the Jena project for
> > now. I
> > > am not looking at an alternative to JSON-LD, correct my if I am wrong but
> > > as far as my limited understanding of JSON-LD goes it is a way to
> > > store/serialize RDF like data in a json format. while my use case would
> > be
> > > a customer that presents any data in json and wants me to read this into
> > a
> > > sparql endpoint for further inspection (with bnodes for arrays, warts and
> > > all). Currently I have to programmatically write transformations to allow
> > > me to read the data into a Jena store. Can JSON-LD already help me with
> > > this task?
> > >
> > >
> > >
> > > On Thu, Nov 29, 2018 at 12:47 PM ajs6f <aj...@apache.org> wrote:
> > >
> > > > I agree _very heartily_ with the caution that Andy and Marco are
> > > > expressing. I've been following the conversation on
> > semantic-web@w3.org
> > > > and I have yet to hear anything that seems very useful or practical to
> > me.
> > > >
> > > > That having been said, and speaking very much as a member of W3C's
> > JSON-LD
> > > > Working Group, I'm also not ecstatic about setting up an alternative to
> > > > JSON-LD. Perhaps you could say a little about why it's not a good
> > choice
> > > > for data access? I would hope that you would be able to equip your
> > generic
> > > > JSON with a JSON-LD context and roll on without any special new Jena
> > > > tooling needed... is that not possible (or optimal) for some reason? If
> > > > it's related to Jena, we can talk about it here, and if it's related to
> > > > JSON-LD, I'd be very happy to take your concern to the WG.
> > > >
> > > > ajs6f
> > > >
> > > > > On Nov 29, 2018, at 7:40 AM, Marco Neumann <ma...@gmail.com>
> > > > wrote:
> > > > >
> > > > > I agree Andy, there is no need to rush things here and break the API.
> > > > Maybe
> > > > > we could provide an in memory model for "Generalized RDF" as sandbox
> > for
> > > > > people to play with. But what I'd like to see are more bridges to the
> > > > json
> > > > > community as it has become the defacto lingua franca for data
> > exchange on
> > > > > the web now.
> > > > >
> > > > > In particular with regards to generic json rather than json-ld.
> > possibly
> > > > a
> > > > > generic mapping to a json dataset assembler could work for data
> > access
> > > > and
> > > > > transformation. has anybody done anything here already?
> > > > >
> > > > >
> > > > > On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org>
> > wrote:
> > > > >
> > > > >> Internally, that means Graph/Node/Triple and the ARQ engine, Jena
> > really
> > > > >> works on what is called "Generalized RDF" in RDF 1.1 - so literals
> > as
> > > > >> subjects, literals as predicates blank nodes as predicates - work
> > just
> > > > >> fine. Whether they are a good idea is a different question.
> > > > >>
> > > > >> RDF* works as well (in-memory graphs). Jena has Node_Triple and
> > > > >> Node_Graph nowadays for completeness.
> > > > >>
> > > > >> If we get into structured values (lists not encoded in triples,
> > > > >> sets/bags as datastructures - and these are things property graphs
> > and
> > > > >> traditionally SQL also find it hard to handle), there would be work
> > to
> > > > >> do, but it's not impossible.
> > > > >>
> > > > >> The impact is on the Model API is where the impact is.
> > > > >>
> > > > >> Personal opinion about changing the core specs:
> > > > >>
> > > > >> Being "better"isn't enough. There is lots of investment in people's
> > > > >> time and energy has gone in to learning about RDF and communicating
> > > > >> about RDF.
> > > > >>
> > > > >> The impact is when new data meets old apps but also existing
> > > > >> thinking/learning/blogs/books/...
> > > > >>
> > > > >> Changes to the basics need to meet a higher barrier than "better".
> > > > >>
> > > > >> Andy
> > > > >>
> > > > >> On 22/11/2018 13:13, Marco Neumann wrote:
> > > > >>> are we prepared in Jena for such a move on the RDF syntax?
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>> ---------- Forwarded message ---------
> > > > >>> From: Tim Berners-Lee <ti...@w3.org>
> > > > >>> Date: Thu, Nov 22, 2018 at 1:05 PM
> > > > >>> Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
> > > > >>> To: David Booth <da...@dbooth.org>
> > > > >>> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <
> > > > danbri@google.com
> > > > >>> ,
> > > > >>> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <
> > olaf.hartig@liu.se
> > > > >,
> > > > >>> Axel Polleres <ax...@polleres.net>
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
> > > > >>>
> > > > >>> 7. Literals as subjects. RDF should allow "anyone to say
> > > > >>> anything about anything", but RDF does not currently allow
> > > > >>> literals as subjects! (One work-around is to use -- you guessed
> > > > >>> it -- a blank node, which in turn is asserted to be owl:sameAs
> > > > >>> the literal.) This deficiency may seem unimportant relative
> > > > >>> to other RDF difficulties, but it is a peculiar anomaly that
> > > > >>> may have greater impact than we realize. Imagine an *average*
> > > > >>> developer, new to RDF, who unknowingly violates this rule and
> > > > >>> is puzzled when it doesn't work. Negative experiences like
> > > > >>> that drive people away. Even more insidiously, imagine this
> > > > >>> developer tries to CONSTRUCT triples using a SPARQL query,
> > > > >>> and some of those triples happen to have literals in the
> > > > >>> subject position. Per the SPARQL standard, those triples will
> > > > >>> be silently eliminated from the results,[13] which could lead
> > > > >>> to silently producing wrong answers from the application --
> > > > >>> the worst of all possible bugs.
> > > > >>>
> > > > >>>
> > > > >>> Agreed.
> > > > >>>
> > > > >>> I thought we had fixed that in some later spec but I guess not.
> > > > >>>
> > > > >>> All code I have written, like cwm and rdflib.js, allows the same
> > things
> > > > >> in
> > > > >>> subject and object positions. Life is too short for arbitrary
> > > > >> unnecessary
> > > > >>> asymmetry.
> > > > >>>
> > > > >>> timbl
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>
> > > > >
> > > > >
> > > > > --
> > > > >
> > > > >
> > > > > ---
> > > > > Marco Neumann
> > > > > KONA
> > > >
> > > >
> > >
> > > --
> > >
> > >
> > > ---
> > > Marco Neumann
> > > KONA
> >
> --
>
>
> ---
> Marco Neumann
> KONA
Re: JSON & JENA Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by Marco Neumann <ma...@gmail.com>.
thanks for the link Martynas, one still has to go to rdf from xml. I find
the data assembler in jena/d2rq more convenient but am open to new ideas.
btw I never quite know who is posting on ajs6f hence the misnomer
On Thu 29. Nov 2018 at 14:29, Martynas Jusevičius <ma...@atomgraph.com>
wrote:
> Marco,
>
> FYI XSLT 3.0 supports JSON transformations:
> https://www.w3.org/TR/xslt-30/#json
>
> Martynas
> On Thu, Nov 29, 2018 at 2:27 PM Marco Neumann <ma...@gmail.com>
> wrote:
> >
> > good to know that we are on the same page here Adam. With regards to json
> > let's limit the scope of the discussion here to the Jena project for
> now. I
> > am not looking at an alternative to JSON-LD, correct my if I am wrong but
> > as far as my limited understanding of JSON-LD goes it is a way to
> > store/serialize RDF like data in a json format. while my use case would
> be
> > a customer that presents any data in json and wants me to read this into
> a
> > sparql endpoint for further inspection (with bnodes for arrays, warts and
> > all). Currently I have to programmatically write transformations to allow
> > me to read the data into a Jena store. Can JSON-LD already help me with
> > this task?
> >
> >
> >
> > On Thu, Nov 29, 2018 at 12:47 PM ajs6f <aj...@apache.org> wrote:
> >
> > > I agree _very heartily_ with the caution that Andy and Marco are
> > > expressing. I've been following the conversation on
> semantic-web@w3.org
> > > and I have yet to hear anything that seems very useful or practical to
> me.
> > >
> > > That having been said, and speaking very much as a member of W3C's
> JSON-LD
> > > Working Group, I'm also not ecstatic about setting up an alternative to
> > > JSON-LD. Perhaps you could say a little about why it's not a good
> choice
> > > for data access? I would hope that you would be able to equip your
> generic
> > > JSON with a JSON-LD context and roll on without any special new Jena
> > > tooling needed... is that not possible (or optimal) for some reason? If
> > > it's related to Jena, we can talk about it here, and if it's related to
> > > JSON-LD, I'd be very happy to take your concern to the WG.
> > >
> > > ajs6f
> > >
> > > > On Nov 29, 2018, at 7:40 AM, Marco Neumann <ma...@gmail.com>
> > > wrote:
> > > >
> > > > I agree Andy, there is no need to rush things here and break the API.
> > > Maybe
> > > > we could provide an in memory model for "Generalized RDF" as sandbox
> for
> > > > people to play with. But what I'd like to see are more bridges to the
> > > json
> > > > community as it has become the defacto lingua franca for data
> exchange on
> > > > the web now.
> > > >
> > > > In particular with regards to generic json rather than json-ld.
> possibly
> > > a
> > > > generic mapping to a json dataset assembler could work for data
> access
> > > and
> > > > transformation. has anybody done anything here already?
> > > >
> > > >
> > > > On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org>
> wrote:
> > > >
> > > >> Internally, that means Graph/Node/Triple and the ARQ engine, Jena
> really
> > > >> works on what is called "Generalized RDF" in RDF 1.1 - so literals
> as
> > > >> subjects, literals as predicates blank nodes as predicates - work
> just
> > > >> fine. Whether they are a good idea is a different question.
> > > >>
> > > >> RDF* works as well (in-memory graphs). Jena has Node_Triple and
> > > >> Node_Graph nowadays for completeness.
> > > >>
> > > >> If we get into structured values (lists not encoded in triples,
> > > >> sets/bags as datastructures - and these are things property graphs
> and
> > > >> traditionally SQL also find it hard to handle), there would be work
> to
> > > >> do, but it's not impossible.
> > > >>
> > > >> The impact is on the Model API is where the impact is.
> > > >>
> > > >> Personal opinion about changing the core specs:
> > > >>
> > > >> Being "better"isn't enough. There is lots of investment in people's
> > > >> time and energy has gone in to learning about RDF and communicating
> > > >> about RDF.
> > > >>
> > > >> The impact is when new data meets old apps but also existing
> > > >> thinking/learning/blogs/books/...
> > > >>
> > > >> Changes to the basics need to meet a higher barrier than "better".
> > > >>
> > > >> Andy
> > > >>
> > > >> On 22/11/2018 13:13, Marco Neumann wrote:
> > > >>> are we prepared in Jena for such a move on the RDF syntax?
> > > >>>
> > > >>>
> > > >>>
> > > >>> ---------- Forwarded message ---------
> > > >>> From: Tim Berners-Lee <ti...@w3.org>
> > > >>> Date: Thu, Nov 22, 2018 at 1:05 PM
> > > >>> Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
> > > >>> To: David Booth <da...@dbooth.org>
> > > >>> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <
> > > danbri@google.com
> > > >>> ,
> > > >>> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <
> olaf.hartig@liu.se
> > > >,
> > > >>> Axel Polleres <ax...@polleres.net>
> > > >>>
> > > >>>
> > > >>>
> > > >>>
> > > >>> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
> > > >>>
> > > >>> 7. Literals as subjects. RDF should allow "anyone to say
> > > >>> anything about anything", but RDF does not currently allow
> > > >>> literals as subjects! (One work-around is to use -- you guessed
> > > >>> it -- a blank node, which in turn is asserted to be owl:sameAs
> > > >>> the literal.) This deficiency may seem unimportant relative
> > > >>> to other RDF difficulties, but it is a peculiar anomaly that
> > > >>> may have greater impact than we realize. Imagine an *average*
> > > >>> developer, new to RDF, who unknowingly violates this rule and
> > > >>> is puzzled when it doesn't work. Negative experiences like
> > > >>> that drive people away. Even more insidiously, imagine this
> > > >>> developer tries to CONSTRUCT triples using a SPARQL query,
> > > >>> and some of those triples happen to have literals in the
> > > >>> subject position. Per the SPARQL standard, those triples will
> > > >>> be silently eliminated from the results,[13] which could lead
> > > >>> to silently producing wrong answers from the application --
> > > >>> the worst of all possible bugs.
> > > >>>
> > > >>>
> > > >>> Agreed.
> > > >>>
> > > >>> I thought we had fixed that in some later spec but I guess not.
> > > >>>
> > > >>> All code I have written, like cwm and rdflib.js, allows the same
> things
> > > >> in
> > > >>> subject and object positions. Life is too short for arbitrary
> > > >> unnecessary
> > > >>> asymmetry.
> > > >>>
> > > >>> timbl
> > > >>>
> > > >>>
> > > >>>
> > > >>
> > > >
> > > >
> > > > --
> > > >
> > > >
> > > > ---
> > > > Marco Neumann
> > > > KONA
> > >
> > >
> >
> > --
> >
> >
> > ---
> > Marco Neumann
> > KONA
>
--
---
Marco Neumann
KONA
Re: JSON & JENA Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by Martynas Jusevičius <ma...@atomgraph.com>.
Marco,
FYI XSLT 3.0 supports JSON transformations: https://www.w3.org/TR/xslt-30/#json
Martynas
On Thu, Nov 29, 2018 at 2:27 PM Marco Neumann <ma...@gmail.com> wrote:
>
> good to know that we are on the same page here Adam. With regards to json
> let's limit the scope of the discussion here to the Jena project for now. I
> am not looking at an alternative to JSON-LD, correct my if I am wrong but
> as far as my limited understanding of JSON-LD goes it is a way to
> store/serialize RDF like data in a json format. while my use case would be
> a customer that presents any data in json and wants me to read this into a
> sparql endpoint for further inspection (with bnodes for arrays, warts and
> all). Currently I have to programmatically write transformations to allow
> me to read the data into a Jena store. Can JSON-LD already help me with
> this task?
>
>
>
> On Thu, Nov 29, 2018 at 12:47 PM ajs6f <aj...@apache.org> wrote:
>
> > I agree _very heartily_ with the caution that Andy and Marco are
> > expressing. I've been following the conversation on semantic-web@w3.org
> > and I have yet to hear anything that seems very useful or practical to me.
> >
> > That having been said, and speaking very much as a member of W3C's JSON-LD
> > Working Group, I'm also not ecstatic about setting up an alternative to
> > JSON-LD. Perhaps you could say a little about why it's not a good choice
> > for data access? I would hope that you would be able to equip your generic
> > JSON with a JSON-LD context and roll on without any special new Jena
> > tooling needed... is that not possible (or optimal) for some reason? If
> > it's related to Jena, we can talk about it here, and if it's related to
> > JSON-LD, I'd be very happy to take your concern to the WG.
> >
> > ajs6f
> >
> > > On Nov 29, 2018, at 7:40 AM, Marco Neumann <ma...@gmail.com>
> > wrote:
> > >
> > > I agree Andy, there is no need to rush things here and break the API.
> > Maybe
> > > we could provide an in memory model for "Generalized RDF" as sandbox for
> > > people to play with. But what I'd like to see are more bridges to the
> > json
> > > community as it has become the defacto lingua franca for data exchange on
> > > the web now.
> > >
> > > In particular with regards to generic json rather than json-ld. possibly
> > a
> > > generic mapping to a json dataset assembler could work for data access
> > and
> > > transformation. has anybody done anything here already?
> > >
> > >
> > > On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org> wrote:
> > >
> > >> Internally, that means Graph/Node/Triple and the ARQ engine, Jena really
> > >> works on what is called "Generalized RDF" in RDF 1.1 - so literals as
> > >> subjects, literals as predicates blank nodes as predicates - work just
> > >> fine. Whether they are a good idea is a different question.
> > >>
> > >> RDF* works as well (in-memory graphs). Jena has Node_Triple and
> > >> Node_Graph nowadays for completeness.
> > >>
> > >> If we get into structured values (lists not encoded in triples,
> > >> sets/bags as datastructures - and these are things property graphs and
> > >> traditionally SQL also find it hard to handle), there would be work to
> > >> do, but it's not impossible.
> > >>
> > >> The impact is on the Model API is where the impact is.
> > >>
> > >> Personal opinion about changing the core specs:
> > >>
> > >> Being "better"isn't enough. There is lots of investment in people's
> > >> time and energy has gone in to learning about RDF and communicating
> > >> about RDF.
> > >>
> > >> The impact is when new data meets old apps but also existing
> > >> thinking/learning/blogs/books/...
> > >>
> > >> Changes to the basics need to meet a higher barrier than "better".
> > >>
> > >> Andy
> > >>
> > >> On 22/11/2018 13:13, Marco Neumann wrote:
> > >>> are we prepared in Jena for such a move on the RDF syntax?
> > >>>
> > >>>
> > >>>
> > >>> ---------- Forwarded message ---------
> > >>> From: Tim Berners-Lee <ti...@w3.org>
> > >>> Date: Thu, Nov 22, 2018 at 1:05 PM
> > >>> Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
> > >>> To: David Booth <da...@dbooth.org>
> > >>> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <
> > danbri@google.com
> > >>> ,
> > >>> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <olaf.hartig@liu.se
> > >,
> > >>> Axel Polleres <ax...@polleres.net>
> > >>>
> > >>>
> > >>>
> > >>>
> > >>> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
> > >>>
> > >>> 7. Literals as subjects. RDF should allow "anyone to say
> > >>> anything about anything", but RDF does not currently allow
> > >>> literals as subjects! (One work-around is to use -- you guessed
> > >>> it -- a blank node, which in turn is asserted to be owl:sameAs
> > >>> the literal.) This deficiency may seem unimportant relative
> > >>> to other RDF difficulties, but it is a peculiar anomaly that
> > >>> may have greater impact than we realize. Imagine an *average*
> > >>> developer, new to RDF, who unknowingly violates this rule and
> > >>> is puzzled when it doesn't work. Negative experiences like
> > >>> that drive people away. Even more insidiously, imagine this
> > >>> developer tries to CONSTRUCT triples using a SPARQL query,
> > >>> and some of those triples happen to have literals in the
> > >>> subject position. Per the SPARQL standard, those triples will
> > >>> be silently eliminated from the results,[13] which could lead
> > >>> to silently producing wrong answers from the application --
> > >>> the worst of all possible bugs.
> > >>>
> > >>>
> > >>> Agreed.
> > >>>
> > >>> I thought we had fixed that in some later spec but I guess not.
> > >>>
> > >>> All code I have written, like cwm and rdflib.js, allows the same things
> > >> in
> > >>> subject and object positions. Life is too short for arbitrary
> > >> unnecessary
> > >>> asymmetry.
> > >>>
> > >>> timbl
> > >>>
> > >>>
> > >>>
> > >>
> > >
> > >
> > > --
> > >
> > >
> > > ---
> > > Marco Neumann
> > > KONA
> >
> >
>
> --
>
>
> ---
> Marco Neumann
> KONA
JSON & JENA Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by Marco Neumann <ma...@gmail.com>.
good to know that we are on the same page here Adam. With regards to json
let's limit the scope of the discussion here to the Jena project for now. I
am not looking at an alternative to JSON-LD, correct my if I am wrong but
as far as my limited understanding of JSON-LD goes it is a way to
store/serialize RDF like data in a json format. while my use case would be
a customer that presents any data in json and wants me to read this into a
sparql endpoint for further inspection (with bnodes for arrays, warts and
all). Currently I have to programmatically write transformations to allow
me to read the data into a Jena store. Can JSON-LD already help me with
this task?
On Thu, Nov 29, 2018 at 12:47 PM ajs6f <aj...@apache.org> wrote:
> I agree _very heartily_ with the caution that Andy and Marco are
> expressing. I've been following the conversation on semantic-web@w3.org
> and I have yet to hear anything that seems very useful or practical to me.
>
> That having been said, and speaking very much as a member of W3C's JSON-LD
> Working Group, I'm also not ecstatic about setting up an alternative to
> JSON-LD. Perhaps you could say a little about why it's not a good choice
> for data access? I would hope that you would be able to equip your generic
> JSON with a JSON-LD context and roll on without any special new Jena
> tooling needed... is that not possible (or optimal) for some reason? If
> it's related to Jena, we can talk about it here, and if it's related to
> JSON-LD, I'd be very happy to take your concern to the WG.
>
> ajs6f
>
> > On Nov 29, 2018, at 7:40 AM, Marco Neumann <ma...@gmail.com>
> wrote:
> >
> > I agree Andy, there is no need to rush things here and break the API.
> Maybe
> > we could provide an in memory model for "Generalized RDF" as sandbox for
> > people to play with. But what I'd like to see are more bridges to the
> json
> > community as it has become the defacto lingua franca for data exchange on
> > the web now.
> >
> > In particular with regards to generic json rather than json-ld. possibly
> a
> > generic mapping to a json dataset assembler could work for data access
> and
> > transformation. has anybody done anything here already?
> >
> >
> > On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org> wrote:
> >
> >> Internally, that means Graph/Node/Triple and the ARQ engine, Jena really
> >> works on what is called "Generalized RDF" in RDF 1.1 - so literals as
> >> subjects, literals as predicates blank nodes as predicates - work just
> >> fine. Whether they are a good idea is a different question.
> >>
> >> RDF* works as well (in-memory graphs). Jena has Node_Triple and
> >> Node_Graph nowadays for completeness.
> >>
> >> If we get into structured values (lists not encoded in triples,
> >> sets/bags as datastructures - and these are things property graphs and
> >> traditionally SQL also find it hard to handle), there would be work to
> >> do, but it's not impossible.
> >>
> >> The impact is on the Model API is where the impact is.
> >>
> >> Personal opinion about changing the core specs:
> >>
> >> Being "better"isn't enough. There is lots of investment in people's
> >> time and energy has gone in to learning about RDF and communicating
> >> about RDF.
> >>
> >> The impact is when new data meets old apps but also existing
> >> thinking/learning/blogs/books/...
> >>
> >> Changes to the basics need to meet a higher barrier than "better".
> >>
> >> Andy
> >>
> >> On 22/11/2018 13:13, Marco Neumann wrote:
> >>> are we prepared in Jena for such a move on the RDF syntax?
> >>>
> >>>
> >>>
> >>> ---------- Forwarded message ---------
> >>> From: Tim Berners-Lee <ti...@w3.org>
> >>> Date: Thu, Nov 22, 2018 at 1:05 PM
> >>> Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
> >>> To: David Booth <da...@dbooth.org>
> >>> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <
> danbri@google.com
> >>> ,
> >>> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <olaf.hartig@liu.se
> >,
> >>> Axel Polleres <ax...@polleres.net>
> >>>
> >>>
> >>>
> >>>
> >>> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
> >>>
> >>> 7. Literals as subjects. RDF should allow "anyone to say
> >>> anything about anything", but RDF does not currently allow
> >>> literals as subjects! (One work-around is to use -- you guessed
> >>> it -- a blank node, which in turn is asserted to be owl:sameAs
> >>> the literal.) This deficiency may seem unimportant relative
> >>> to other RDF difficulties, but it is a peculiar anomaly that
> >>> may have greater impact than we realize. Imagine an *average*
> >>> developer, new to RDF, who unknowingly violates this rule and
> >>> is puzzled when it doesn't work. Negative experiences like
> >>> that drive people away. Even more insidiously, imagine this
> >>> developer tries to CONSTRUCT triples using a SPARQL query,
> >>> and some of those triples happen to have literals in the
> >>> subject position. Per the SPARQL standard, those triples will
> >>> be silently eliminated from the results,[13] which could lead
> >>> to silently producing wrong answers from the application --
> >>> the worst of all possible bugs.
> >>>
> >>>
> >>> Agreed.
> >>>
> >>> I thought we had fixed that in some later spec but I guess not.
> >>>
> >>> All code I have written, like cwm and rdflib.js, allows the same things
> >> in
> >>> subject and object positions. Life is too short for arbitrary
> >> unnecessary
> >>> asymmetry.
> >>>
> >>> timbl
> >>>
> >>>
> >>>
> >>
> >
> >
> > --
> >
> >
> > ---
> > Marco Neumann
> > KONA
>
>
--
---
Marco Neumann
KONA
Re: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by ajs6f <aj...@apache.org>.
I agree _very heartily_ with the caution that Andy and Marco are expressing. I've been following the conversation on semantic-web@w3.org and I have yet to hear anything that seems very useful or practical to me.
That having been said, and speaking very much as a member of W3C's JSON-LD Working Group, I'm also not ecstatic about setting up an alternative to JSON-LD. Perhaps you could say a little about why it's not a good choice for data access? I would hope that you would be able to equip your generic JSON with a JSON-LD context and roll on without any special new Jena tooling needed... is that not possible (or optimal) for some reason? If it's related to Jena, we can talk about it here, and if it's related to JSON-LD, I'd be very happy to take your concern to the WG.
ajs6f
> On Nov 29, 2018, at 7:40 AM, Marco Neumann <ma...@gmail.com> wrote:
>
> I agree Andy, there is no need to rush things here and break the API. Maybe
> we could provide an in memory model for "Generalized RDF" as sandbox for
> people to play with. But what I'd like to see are more bridges to the json
> community as it has become the defacto lingua franca for data exchange on
> the web now.
>
> In particular with regards to generic json rather than json-ld. possibly a
> generic mapping to a json dataset assembler could work for data access and
> transformation. has anybody done anything here already?
>
>
> On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org> wrote:
>
>> Internally, that means Graph/Node/Triple and the ARQ engine, Jena really
>> works on what is called "Generalized RDF" in RDF 1.1 - so literals as
>> subjects, literals as predicates blank nodes as predicates - work just
>> fine. Whether they are a good idea is a different question.
>>
>> RDF* works as well (in-memory graphs). Jena has Node_Triple and
>> Node_Graph nowadays for completeness.
>>
>> If we get into structured values (lists not encoded in triples,
>> sets/bags as datastructures - and these are things property graphs and
>> traditionally SQL also find it hard to handle), there would be work to
>> do, but it's not impossible.
>>
>> The impact is on the Model API is where the impact is.
>>
>> Personal opinion about changing the core specs:
>>
>> Being "better"isn't enough. There is lots of investment in people's
>> time and energy has gone in to learning about RDF and communicating
>> about RDF.
>>
>> The impact is when new data meets old apps but also existing
>> thinking/learning/blogs/books/...
>>
>> Changes to the basics need to meet a higher barrier than "better".
>>
>> Andy
>>
>> On 22/11/2018 13:13, Marco Neumann wrote:
>>> are we prepared in Jena for such a move on the RDF syntax?
>>>
>>>
>>>
>>> ---------- Forwarded message ---------
>>> From: Tim Berners-Lee <ti...@w3.org>
>>> Date: Thu, Nov 22, 2018 at 1:05 PM
>>> Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
>>> To: David Booth <da...@dbooth.org>
>>> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <danbri@google.com
>>> ,
>>> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <ol...@liu.se>,
>>> Axel Polleres <ax...@polleres.net>
>>>
>>>
>>>
>>>
>>> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
>>>
>>> 7. Literals as subjects. RDF should allow "anyone to say
>>> anything about anything", but RDF does not currently allow
>>> literals as subjects! (One work-around is to use -- you guessed
>>> it -- a blank node, which in turn is asserted to be owl:sameAs
>>> the literal.) This deficiency may seem unimportant relative
>>> to other RDF difficulties, but it is a peculiar anomaly that
>>> may have greater impact than we realize. Imagine an *average*
>>> developer, new to RDF, who unknowingly violates this rule and
>>> is puzzled when it doesn't work. Negative experiences like
>>> that drive people away. Even more insidiously, imagine this
>>> developer tries to CONSTRUCT triples using a SPARQL query,
>>> and some of those triples happen to have literals in the
>>> subject position. Per the SPARQL standard, those triples will
>>> be silently eliminated from the results,[13] which could lead
>>> to silently producing wrong answers from the application --
>>> the worst of all possible bugs.
>>>
>>>
>>> Agreed.
>>>
>>> I thought we had fixed that in some later spec but I guess not.
>>>
>>> All code I have written, like cwm and rdflib.js, allows the same things
>> in
>>> subject and object positions. Life is too short for arbitrary
>> unnecessary
>>> asymmetry.
>>>
>>> timbl
>>>
>>>
>>>
>>
>
>
> --
>
>
> ---
> Marco Neumann
> KONA
Re: Fwd: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by Marco Neumann <ma...@gmail.com>.
I agree Andy, there is no need to rush things here and break the API. Maybe
we could provide an in memory model for "Generalized RDF" as sandbox for
people to play with. But what I'd like to see are more bridges to the json
community as it has become the defacto lingua franca for data exchange on
the web now.
In particular with regards to generic json rather than json-ld. possibly a
generic mapping to a json dataset assembler could work for data access and
transformation. has anybody done anything here already?
On Thu, Nov 22, 2018 at 2:11 PM Andy Seaborne <an...@apache.org> wrote:
> Internally, that means Graph/Node/Triple and the ARQ engine, Jena really
> works on what is called "Generalized RDF" in RDF 1.1 - so literals as
> subjects, literals as predicates blank nodes as predicates - work just
> fine. Whether they are a good idea is a different question.
>
> RDF* works as well (in-memory graphs). Jena has Node_Triple and
> Node_Graph nowadays for completeness.
>
> If we get into structured values (lists not encoded in triples,
> sets/bags as datastructures - and these are things property graphs and
> traditionally SQL also find it hard to handle), there would be work to
> do, but it's not impossible.
>
> The impact is on the Model API is where the impact is.
>
> Personal opinion about changing the core specs:
>
> Being "better"isn't enough. There is lots of investment in people's
> time and energy has gone in to learning about RDF and communicating
> about RDF.
>
> The impact is when new data meets old apps but also existing
> thinking/learning/blogs/books/...
>
> Changes to the basics need to meet a higher barrier than "better".
>
> Andy
>
> On 22/11/2018 13:13, Marco Neumann wrote:
> > are we prepared in Jena for such a move on the RDF syntax?
> >
> >
> >
> > ---------- Forwarded message ---------
> > From: Tim Berners-Lee <ti...@w3.org>
> > Date: Thu, Nov 22, 2018 at 1:05 PM
> > Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
> > To: David Booth <da...@dbooth.org>
> > Cc: SW-forum Web <se...@w3.org>, Dan Brickley <danbri@google.com
> >,
> > Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <ol...@liu.se>,
> > Axel Polleres <ax...@polleres.net>
> >
> >
> >
> >
> > On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
> >
> > 7. Literals as subjects. RDF should allow "anyone to say
> > anything about anything", but RDF does not currently allow
> > literals as subjects! (One work-around is to use -- you guessed
> > it -- a blank node, which in turn is asserted to be owl:sameAs
> > the literal.) This deficiency may seem unimportant relative
> > to other RDF difficulties, but it is a peculiar anomaly that
> > may have greater impact than we realize. Imagine an *average*
> > developer, new to RDF, who unknowingly violates this rule and
> > is puzzled when it doesn't work. Negative experiences like
> > that drive people away. Even more insidiously, imagine this
> > developer tries to CONSTRUCT triples using a SPARQL query,
> > and some of those triples happen to have literals in the
> > subject position. Per the SPARQL standard, those triples will
> > be silently eliminated from the results,[13] which could lead
> > to silently producing wrong answers from the application --
> > the worst of all possible bugs.
> >
> >
> > Agreed.
> >
> > I thought we had fixed that in some later spec but I guess not.
> >
> > All code I have written, like cwm and rdflib.js, allows the same things
> in
> > subject and object positions. Life is too short for arbitrary
> unnecessary
> > asymmetry.
> >
> > timbl
> >
> >
> >
>
--
---
Marco Neumann
KONA
Re: Fwd: ✅ Literals as subjects Re: Toward easier RDF: a proposal
Posted by Andy Seaborne <an...@apache.org>.
Internally, that means Graph/Node/Triple and the ARQ engine, Jena really
works on what is called "Generalized RDF" in RDF 1.1 - so literals as
subjects, literals as predicates blank nodes as predicates - work just
fine. Whether they are a good idea is a different question.
RDF* works as well (in-memory graphs). Jena has Node_Triple and
Node_Graph nowadays for completeness.
If we get into structured values (lists not encoded in triples,
sets/bags as datastructures - and these are things property graphs and
traditionally SQL also find it hard to handle), there would be work to
do, but it's not impossible.
The impact is on the Model API is where the impact is.
Personal opinion about changing the core specs:
Being "better"isn't enough. There is lots of investment in people's
time and energy has gone in to learning about RDF and communicating
about RDF.
The impact is when new data meets old apps but also existing
thinking/learning/blogs/books/...
Changes to the basics need to meet a higher barrier than "better".
Andy
On 22/11/2018 13:13, Marco Neumann wrote:
> are we prepared in Jena for such a move on the RDF syntax?
>
>
>
> ---------- Forwarded message ---------
> From: Tim Berners-Lee <ti...@w3.org>
> Date: Thu, Nov 22, 2018 at 1:05 PM
> Subject: ✅ Literals as subjects Re: Toward easier RDF: a proposal
> To: David Booth <da...@dbooth.org>
> Cc: SW-forum Web <se...@w3.org>, Dan Brickley <da...@google.com>,
> Sean B. Palmer <se...@miscoranda.com>, Olaf Hartig <ol...@liu.se>,
> Axel Polleres <ax...@polleres.net>
>
>
>
>
> On 2018-11 -21, at 22:40, David Booth <da...@dbooth.org> wrote:
>
> 7. Literals as subjects. RDF should allow "anyone to say
> anything about anything", but RDF does not currently allow
> literals as subjects! (One work-around is to use -- you guessed
> it -- a blank node, which in turn is asserted to be owl:sameAs
> the literal.) This deficiency may seem unimportant relative
> to other RDF difficulties, but it is a peculiar anomaly that
> may have greater impact than we realize. Imagine an *average*
> developer, new to RDF, who unknowingly violates this rule and
> is puzzled when it doesn't work. Negative experiences like
> that drive people away. Even more insidiously, imagine this
> developer tries to CONSTRUCT triples using a SPARQL query,
> and some of those triples happen to have literals in the
> subject position. Per the SPARQL standard, those triples will
> be silently eliminated from the results,[13] which could lead
> to silently producing wrong answers from the application --
> the worst of all possible bugs.
>
>
> Agreed.
>
> I thought we had fixed that in some later spec but I guess not.
>
> All code I have written, like cwm and rdflib.js, allows the same things in
> subject and object positions. Life is too short for arbitrary unnecessary
> asymmetry.
>
> timbl
>
>
>