Hi using json-ld is indeed rather simple, as it is JSON, and then it's even possible to index it as is. I'm currently using ES for storing RDF documents in json-ld on a specific index: in that case one can simply use the uri as an _id, recover the full original format by _source, and use basic search capabilities on the index, if escaping / nesting it's not a big deal.
However, in order to use resource with some more flexibility, I think the best would be index them as "flat" as possible, then use an ad-hoc @context on the ES json to obtain again the original json-ld. This would be my ideal usage at the moment: seems complex at first, but it's not, I'm currently experimenting in saving @context for a _type, obtaining let's say a sort of _context, similar to a _mapping, to reconstruct the original semantics. If someone likes the idea, I'd like to share thoughts on that :-) Il giorno venerdì 26 settembre 2014 14:08:07 UTC+2, Jörg Prante ha scritto: > > Lukáš, > > of course you are right, RDF/XML looks complex and requires parsing. The > underlying principle of all RDF is a graph (or a series of triples in form > of subject/predicate/object, where the triple series is a serialization of > the graph), So the challenge is first the parsing of RDF input, and second, > constructing the model, and third, serializing the model to an ES-friendly > input (here: JSON-LD, sort of). RDF ensures that there is a single model > for all serializations. > > This technical perspective does not necessarily solve all challenges that > are inherent to the chosen data model. For example, nested resources in > RDF. It might be feasible to flatten nested resource by their identifiers > and generate one JSON after the other. Or it could be feasible to keep > nested resources intact and wrap them into nested structures in a single ES > JSON object. > > In my data model, I can map RDF subject IDs to ES doc IDs. Other data > models may prefer other approaches to select ES doc IDs. > > Jörg > > > > On Fri, Sep 26, 2014 at 10:11 AM, Lukáš Vlček <lukas...@gmail.com > <javascript:>> wrote: > >> Jörg, >> >> my concern is that RDF/XML allow to express one thing in several ways. >> For example, if you take FOAF specification then there are several ways how >> you can express that one Person knows other Person. One way it using >> reference IDs other way it using nested Person inside other Person. See [1] >> for examples. My understanding is that although both ways express exactly >> the same information they lead to different XML representation and thus to >> different JSON-LD. Not that you can push such data in ES but I wonder if >> you can then have any consistent way of querying such data. >> >> May be there is some way how you can preprocess XML document and convert >> all nested Persons to references (would require arbitrary ID >> construction?). Or something similar. Though I am not sure this would be >> generally applicable approach to any RDF data. >> >> [1] http://www.xml.com/pub/a/2004/02/04/foaf.html >> >> Regards, >> Lukas >> >> On Fri, Sep 26, 2014 at 9:28 AM, joerg...@gmail.com <javascript:> < >> joerg...@gmail.com <javascript:>> wrote: >> >>> JSON-LD is perfect for ES indexing, as long as you use the "compact" >>> form of representation. >>> >>> http://www.w3.org/TR/json-ld-api/#compaction-algorithms >>> >>> Example: >>> >>> >>> https://github.com/lanthaler/JsonLD/blob/master/Test/Fixtures/sample-compacted.jsonld >>> >>> This means you should use short field names and shorten IRIs to a prefix >>> form. This gives a convenient mapping to ES field names (e.g. "dc:title" or >>> "dc:creator"). The '@' fields can also be indexed and they do not control >>> anything special in ES (some @id may be mapped to ES _id but for nested >>> structures this does not match) >>> >>> I use my own RDF API and transform RDF graphs (so not only JSON-LD but >>> also other formats like N-Triples and RDF/XML) into XContent using this >>> method: >>> >>> >>> https://github.com/xbib/xbib/blob/master/content/src/main/java/org/xbib/rdf/content/DefaultResourceContentBuilder.java >>> >>> I plan to extend this content building by interpreting rdf:type and >>> rdf:list etc. to generate correct ES JSON objects and arrays. There is also >>> an amount of work left to do for the plethora of XSD types in RDF literals >>> or for language tags. >>> >>> This will be subsumed into an RDF input/output plugin for an ES-based >>> Linked Data Platform >>> >>> http://www.w3.org/TR/ldp/ >>> >>> but there is no ETA yet. >>> >>> Jörg >>> >>> >>> On Fri, Sep 26, 2014 at 5:08 AM, Lukáš Vlček <lukas...@gmail.com >>> <javascript:>> wrote: >>> >>>> Hi, >>>> >>>> I think you will have to preprocess documents on your side first and >>>> then push into ES individually (you can push in batch). >>>> >>>> As a side note, I would say json-ld is quite low level serialization od >>>> RDF data IMO not optimal for ES indexing. May be better would be to find >>>> some RDF-OOM tool and have your RDF documents mapped to Java POJOs and >>>> serialize POJOs into JSONs instead (you can use Jackson library for that >>>> for example). This will give you better control over whole RDF -> JSON >>>> conversion process. >>>> >>>> Regards, >>>> Lukas >>>> >>>> On Thu, Sep 25, 2014 at 7:21 PM, abo <a...@datavolution.com >>>> <javascript:>> wrote: >>>> >>>>> Hello, >>>>> >>>>> I'm new to Elasticsearch, so forgive me if this is a basic question or >>>>> if it's in some documentation that I haven't read... >>>>> >>>>> I am trying to load a json-ld file into ES. The json-ld file was >>>>> generated from an RDF file, using Jena. The structure starts with: >>>>> >>>>> { >>>>> "@graph" : >>>>> >>>>> followed by the individual "documents", each with: >>>>> >>>>> { >>>>> "@id" : >>>>> >>>>> and a variable number of parameters in each. >>>>> >>>>> My question is how do I load this into ES and ensure that documents >>>>> are individually referenced (as opposed to the entire json-ld file)? >>>>> >>>>> Do I need to doctor this json-ld file further in order to load it? >>>>> >>>>> Thanks for your help. >>>>> >>>>> -- abo >>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "elasticsearch" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to elasticsearc...@googlegroups.com <javascript:>. >>>>> To view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/elasticsearch/ec26bbe7-5bb1-4c50-96c4-8f586e1e0807%40googlegroups.com >>>>> >>>>> <https://groups.google.com/d/msgid/elasticsearch/ec26bbe7-5bb1-4c50-96c4-8f586e1e0807%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "elasticsearch" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to elasticsearc...@googlegroups.com <javascript:>. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/elasticsearch/CAO9cvUYiqGoP5%3DpYkkhLzP17pLXAPN9sQVY9Oxn7AH4EY10xGA%40mail.gmail.com >>>> >>>> <https://groups.google.com/d/msgid/elasticsearch/CAO9cvUYiqGoP5%3DpYkkhLzP17pLXAPN9sQVY9Oxn7AH4EY10xGA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "elasticsearch" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to elasticsearc...@googlegroups.com <javascript:>. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/elasticsearch/CAKdsXoHtOZmTcm1dYWKHxSfjNN%3D%3DqdoVwwvpg3DBEAcJz-xw5A%40mail.gmail.com >>> >>> <https://groups.google.com/d/msgid/elasticsearch/CAKdsXoHtOZmTcm1dYWKHxSfjNN%3D%3DqdoVwwvpg3DBEAcJz-xw5A%40mail.gmail.com?utm_medium=email&utm_source=footer> >>> . >>> >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "elasticsearch" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to elasticsearc...@googlegroups.com <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/elasticsearch/CAO9cvUZXZNtTAVw1Mhr7N%3D03wo7-L1rKqChja45X7EGTEyc2bw%40mail.gmail.com >> >> <https://groups.google.com/d/msgid/elasticsearch/CAO9cvUZXZNtTAVw1Mhr7N%3D03wo7-L1rKqChja45X7EGTEyc2bw%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> >> For more options, visit https://groups.google.com/d/optout. >> > > -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. 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