W3C home > Mailing lists > Public > public-schemaorg@w3.org > June 2015

Re: JSON-LD and multiple values

From: Dan Brickley <danbri@google.com>
Date: Tue, 9 Jun 2015 12:29:03 +0100
Message-ID: <CAK-qy=7efa2nL29TooQ+V43K17-n-4O1=CzqRg-wKWGYUdxdZg@mail.gmail.com>
To: "mfhepp@gmail.com" <mfhepp@gmail.com>
Cc: Melvin Carvalho <melvincarvalho@gmail.com>, Gregg Kellogg <gregg@greggkellogg.net>, Manu Sporny <msporny@digitalbazaar.com>, "schema.org Mailing List" <public-schemaorg@w3.org>
On 9 June 2015 at 10:35, mfhepp@gmail.com <mfhepp@gmail.com> wrote:
> Melvin:
> I might not have made my point clear: This is not a problem of not being able to represent an RDF structure in JSON-LD, but that
>
> 1. the correct pattern in JSON-LD (list/array) is different from the pattern in Turtle, RDFa, RDF/XML etc. (repetition of the same property) and
> 2. that naively using the pattern from the other syntaxes fails *silently* in JSON-LD (just the last value is recognized).

This is broadly analogous to the rule in RDF/XML (inherited from XML
and HTML) that multiple attributes of the same name can't exist. In
RDF/XML that's why we also encoded properties via sub-elements, and
the rule was well known. In JSON, well
https://www.tbray.org/ongoing/When/201x/2013/02/21/JSON-Lesson ...
expresses the situation nicely.

(http://linter.structured-data.org/ doesn't seem to complain btw)

Hopefully we don't have any of these in schema.org's examples. If any
have slipped through, please file a bug -
http://github.com/schemaorg/schemaorg/issues ... I haven't found a
convenient way of checking automatically yet.

Dan

> Try my two examples in the Google Structured Data Testing tool and you will see the difference.
>
> Martin
>
> -----------------------------------
> martin hepp  http://www.heppnetz.de
> mhepp@computer.org          @mfhepp
>
>
>
>
>
>
>
>> On 09 Jun 2015, at 11:23, Melvin Carvalho <melvincarvalho@gmail.com> wrote:
>>
>>
>>
>> On 9 June 2015 at 10:59, mfhepp@gmail.com <mfhepp@gmail.com> wrote:
>> Dear Gregg,
>> dear Manu:
>>
>> I think there is a need for clarifying the proper use of multiple values for the same property in JSON-LD because if I understand it properly, the behavior differs from any other RDF syntax and Microdata (see [1]), as you CANNOT simply repeat a property with different values, as in any other RDF syntax, like so
>>
>> I thought all RDF can be converted to JSON LD?
>>
>> JSON-LD is capable of serializing any RDF graph or dataset and most, but not all, JSON-LD documents can be directly interpreted as RDF as described in RDF 1.1 Concepts [RDF11-CONCEPTS].
>>
>> http://www.w3.org/TR/json-ld/#relationship-to-rdf
>>
>>
>>
>> <script type="application/ld+json">
>> {
>>   "@context": "http://schema.org",
>>   "@type": "Offer",
>>   "businessFunction" : "http://purl.org/goodrelations/v1#Repair",
>>   "businessFunction" : "http://purl.org/goodrelations/v1#Sell"
>>
>> }
>> </script>
>>
>> but instead must use a LIST of values, like so:
>>
>>
>> <script type="application/ld+json">
>> {
>>   "@context": "http://schema.org",
>>   "@type": "Offer",
>>   "businessFunction": ["http://purl.org/goodrelations/v1#Repair", "http://purl.org/goodrelations/v1#Sell" ]
>>
>> }
>> </script>
>>
>> The Google Structured Data Testing Tool shows only the value for the last use of the same property name, but in complex data structures, this will be easy to overlook.
>>
>> We should highlight this prominently (and review all of our examples in schema.org), because otherwise people will have a hard time understanding why only part of their data is understood.
>>
>> In particular, product feature markup with many usages of "additionalProperty" will be prone to this.
>>
>> Best
>>
>> Martin
>>
>> [1] http://webmasters.stackexchange.com/questions/81080/using-productontology-org-to-add-multiple-types/81081#81081
>>
>>
>> -----------------------------------
>> martin hepp  http://www.heppnetz.de
>> mhepp@computer.org          @mfhepp
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
Received on Tuesday, 9 June 2015 11:29:32 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 9 June 2015 11:29:32 UTC