Who has experience with JSON query languages?

Technology
1

I’m looking into how to address bits and pieces of data in JSON (in this context: Support access to a datasets metadata · Issue #22 · cldf/cldfviz · GitHub ).
First, I played around a bit with JSONPath, but then came across JMESPath which seems to be a much better spec (and implementation).
Any experience with or opinions on that topic in the forum?

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2

I have tried a few times to get into this sort of thing. The idea of being able to store not just data but queries in a data format is appealing.

Jq is a similar tool I tried to get used to.

The thing is, for me, I end just going back to filters and maps and so forth in JS, because I feel like I understand those kk d of queries in a step by step way. As soon as you get into wildcards and projections and so forth with the query languages I get lost. Like, this query doesn’t make much sense to me:

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image1028×1795 92 KB

Sorry, that’s not the kind of answer you were looking for, maybe someone else here is familiar — @lgessler? @aryaman?

Oh wait, that quietly does make sense, same as this:

reservations.map(reservation =>
  reservation.instances.map(instance =>
    instance.state)
)
3

For my use case some declarative way to specify such a query is necessary. But most often, this query will be trivial, such as "dc:license". The most complicated stuff I would expect might look like tables[?"dc:conformsTo"=='http://cldf.clld.org/v1.0/terms.rdf#ExampleTable'].url | [0] (in JMESPath).

So what I need is

  1. well specified - ideally with enough documentation around the spec
  2. somewhat familiar/intuitive, or alternatively with hopes of becoming the de-facto standard
  3. Python implementation
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4

JMESPath is used by AWS - so that’s at least giving me hope of it being maintained.

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5

Not familiar with JSON query langs :frowning: I use CLDF for some of my stuff too but I have a script that converts the database to SQL for querying.

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6

@aryaman Yes, that’s an alternative. Do you also dump the CLDF metadata into SQL? And is your script different from the cldf createdb command provided with pycldf?

2 Likes
7

Yes it’s different, it’s a quick script that dumps to SQL for my own purposes, doesn’t use the CLDF metadata (didn’t need it to extend to CLDFs besides my own).

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8

Don’t know much about this space, but this article comparing zq to jq popped up on my feed: Introducing zq: an Easier (and Faster) Alternative to jq | Brim

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9

Oh nice, I always found jq 1) desirable and 2) bewildering! :rofl:

Thanks for sharing this.