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Graph query languages: Cypher vs. Gremlin vs. nGQL

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Re: Graph query languages: Cypher vs. Gremlin vs. nGQL

#21

Post by karatestomp »

EGreg wrote: post #18
motohagiography wrote: post #12

I use cypher most days over the last few years and I like it because it's a complete level of abstraction over the database. In gremlin and this new nGQL, the whole notion of "INSERT," implies that the graph is just a representation over top of a relational db, and power users should understand RDBMS concepts articulated in SQL queries first with this novel and cute graph thingy after for managers. It's like asking E…

I was really attracted to graph databases mainly for the ability to do joins in effectively constant time rather than O(log N) time. But then I realized that sharding and localizing data can accomplish roughly the same thing. Also the graph database doesn’t have to duplicate data so much for joins, saving on memory. If you are going to have a huge dataset, build your data as RDMBS first and then make a cache in a gra…

I came to exactly the same conclusion after having Neo4j pushed on a project by managers who'd been sold by their "it's great for everything!" marketing. At least as of ~2 years ago, no, it wasn't. Fine for a narrow set of query types for data of a very specific kind of shape (dense graph) that you don't care about much and can re-generate if it gets screwed up. Unsuitable as a "database of record" (poor integrity enforcement, transactions very limited) and quite bad (slow, awkward) at a lot of things one might want to do with it, even kinda "graphy" things, that didn't happen to fall in its strengths. Memory hog, too. Seems like most graph databases, though possibly better at some of those things, will tend to be similar, since they have to make trade offs to achieve notably good performance at whatever they're benchmarking to put on their marketing pages.

Cypher was really nice, though.

Re: Graph query languages: Cypher vs. Gremlin vs. nGQL

#22

Post by tasogare »

fils wrote: post #10
gozzoo wrote: post #4

Is anybody still using SPARQL?

Yes.. I work on several projects that leverage SPARQL. The article is also remiss in not mentioning the work the W3C is doing along with Neo4J to do its own alignment ( https://www.w3.org/Data/events/data-ws-2019/ ). Indeed, this article seems very self serving in its omissions. There is a follow up meeting planned soon for that too. Also, much of the work in validation (SHACL, Shex) of graphs leverages SPARQL so it'…

From your link "W3C's RDF uses URIs (Web addresses) for nodes and link labels in directed graphs. This has the advantage of enabling them to be dereferenced to obtain further information, making for a Web of linked data. In particular, nodes can be dereferenced to graphs on remote databases."

I think spreading those kind of lies[1] if a part of why there is a divide between the W3C (at least the RDF community) and the rest of the word. The W3C should be more transparent about RDF capabilities and realistic about the real power of the Semantic Web.

[1] this false because RDF use IRIs not URLs, and not all IRIs are dereferenceable. Moreover, even URLs used as resource id are not constrained to be dereferenceable per the spec (and when they are, you'll get a lot 404 in practice). Also, the same effect can be obtained as easily with properties (key value pair) attached on nodes of graph database.

Re: Graph query languages: Cypher vs. Gremlin vs. nGQL

#23

Post by bjoernbu »

tasogare wrote: post #17
mark_l_watson wrote: post #7

Sorry, but this article fails big time: no mention at all of SPARQL. For application developers, having access to general public Knowledge Graphs like DBPedia and WikiData can be a very good resource. While I am also a big fan of more general graph databases like Neo4J, not even mentioning SPARQL is such a HUGE OMISSION that I have to suspect some commercially motivated bias in this article. The decision of which gra…

Is there any SPARQL implementation that returns results under 10 seconds on a big dataset? Because, I never found a public SPARQL endpoint that gives remotely acceptable response time.

While there may be several things missing for many productive use cases (especially inserts/updates), I think QLever (https://github.com/ad-freiburg/QLever) fits that description very well. There's also a public endpoint linked there.

Re: Graph query languages: Cypher vs. Gremlin vs. nGQL

#24

Post by tannhaeuser »

mark_l_watson wrote: post #7

Sorry, but this article fails big time: no mention at all of SPARQL. For application developers, having access to general public Knowledge Graphs like DBPedia and WikiData can be a very good resource. While I am also a big fan of more general graph databases like Neo4J, not even mentioning SPARQL is such a HUGE OMISSION that I have to suspect some commercially motivated bias in this article. The decision of which gra…

I agree that SPARQL must be considered, and so must Datalog and Prolog. Idk but I'm starting to believe that new-fangled standardization efforts (if you want to call those that) are starting over from scratch and actively avoid looking at prior art as a generation thing. I mean I don't know the people behind gql but I can get that younger devs think there's absolutely no reason that 1985-2010ers had all the fun.

Though I could see why someone wouldn't like SPARQL and RDF, with its bulk reuse of other W3C and TBL concepts such as URLs, resulting in atom and predicate names verbosely and pointlessly beginning with "http://".

Re: Graph query languages: Cypher vs. Gremlin vs. nGQL

#25

Post by carapace »

pgt wrote: post #19

No mention of Datalog? http://www.learndatalogtoday.org/

FWIW there's a Prolog-based graph DB called Terminus: https://medium.com/terminusdb https://github.com/terminusdb

I don't know much about it but they are associated with Seshat Global History Databank http://seshatdatabank.info/ which, if I understand correctly, is something like a serious attempt at "psychohistory" (like in Asimov's Foundation.) https://medium.com/terminusdb/stuffing-the-whole-human-histo...

Re: Graph query languages: Cypher vs. Gremlin vs. nGQL

#26

Post by staticautomatic »

cjlm wrote: post #16
mark_l_watson wrote: post #7

Sorry, but this article fails big time: no mention at all of SPARQL. For application developers, having access to general public Knowledge Graphs like DBPedia and WikiData can be a very good resource. While I am also a big fan of more general graph databases like Neo4J, not even mentioning SPARQL is such a HUGE OMISSION that I have to suspect some commercially motivated bias in this article. The decision of which gra…

How are DBPedia & WikiData useful for application developers? As a reference or for actual integration into applications?

Depending on your domain, they can be super useful, if not indispensable, for Named Entity Recognition.

Re: Graph query languages: Cypher vs. Gremlin vs. nGQL

#27

Post by tannhaeuser »

tasogare wrote: post #22
fils wrote: post #10

Earlier quoted context omitted.

Yes.. I work on several projects that leverage SPARQL. The article is also remiss in not mentioning the work the W3C is doing along with Neo4J to do its own alignment ( https://www.w3.org/Data/events/data-ws-2019/ ). Indeed, this article seems very self serving in its omissions. There is a follow up meeting planned soon for that too. Also, much of the work in validation (SHACL, Shex) of graphs leverages SPARQL so it'…

From your link "W3C's RDF uses URIs (Web addresses) for nodes and link labels in directed graphs. This has the advantage of enabling them to be dereferenced to obtain further information, making for a Web of linked data. In particular, nodes can be dereferenced to graphs on remote databases." I think spreading those kind of lies[1] if a part of why there is a divide between the W3C (at least the RDF community) and th…

I think the reasoning behind RDF using URIs/IRIs for nodes and predicates is that this gives a globally unique naming hierarchy (backed by DNS in turn), such that when combining heterogenous data there's no name clash, and at the same time allows for liberal use in closed DBs via "urn:" URLs. But yeah, if the linked article insinuates that dereferencing RDF URLs is useful or even common, that would be false IMO.

Re: Graph query languages: Cypher vs. Gremlin vs. nGQL

#28

Post by quantified »

I may be missing something, but to any of them let you return information that is not a node in the underlying graph? I had a project once where a user request would result in a graph that was derived: result nodes and edges were derived based on the database’s nodes and edges. Rolled my own system because nothing supported that.

Related, do any of the let you do something simple like return a count of vertices obtained from a traversal, or do you need to walk a result and count them yourself?

Re: Graph query languages: Cypher vs. Gremlin vs. nGQL

#30

Post by matteuan »

tasogare wrote: post #17
mark_l_watson wrote: post #7

Sorry, but this article fails big time: no mention at all of SPARQL. For application developers, having access to general public Knowledge Graphs like DBPedia and WikiData can be a very good resource. While I am also a big fan of more general graph databases like Neo4J, not even mentioning SPARQL is such a HUGE OMISSION that I have to suspect some commercially motivated bias in this article. The decision of which gra…

Is there any SPARQL implementation that returns results under 10 seconds on a big dataset? Because, I never found a public SPARQL endpoint that gives remotely acceptable response time.

Under 10 seconds on which query? If your query involves big joins over a large distributed data-set there won't be a technology that can do it for you. SPARQL is not the problem, you can write the same queries in Cypher or any other language, you will hit the same performance problems
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