On Sat, 2017-02-25 at 10:02 +0000, Kendall Shaw wrote: > [...] > The original post was asking for examples of ways that XQuery is a > good solution for an unknown problem.
Unknown to us at least... yes. > Generally, if I found myself think that technology x is the solution > to every problem, I would proceed as if I am probably wrong about > that. :-) > > It’s interesting to me to know what sorts of applications seem like > they would be a good match for XQuery’s data model but turned out not > to be in some case. I agree that's interesting - I'm afraid I have more experience with what didn't work in SQL and did work with a forest store, probably because I don't often encounter people whose projects didn't fit with XML-related technologies. How do we find them? I do know of people who moved to JSONiq in order to persist JSON documents alongside XML ones, but XQuery 3.1 might well reduce that pressure. Or at least that was a large part of our goal in the XML Query Working Group in developing it, to improve the XML+JSON and JSON- only support. But JSONiq still has the XQuery support there. An example of where I probably would not use an XQuery-based system as my first choice might be where I'm dealing with data coming in from 100,000 sensors at a high rate and I have to store, say, the past hour's worth of data for simple queries. The tree-based collection model works best with data that has hierarchy and is, in SQL terms, semi-structured (i.e. has irregularity). XQuery tends to be a win over SQL when a lot of the queries involve hierarchy or sequence, but if those aspects aren't present it's less obviously a win. Of course, if the sensors are sending EXI-compressed XML parse events, and the db supports that, an XML db can be a win even there; I heard from someone who experimented with devices that could send either JSON or EXI, and he was blown away at the performance improvement he got by switching to EXI. So you have to measure and experiment, too. best, Liam -- Liam R. E. Quin <l...@w3.org> The World Wide Web Consortium (W3C)
