Re: json accessors - Mailing list pgsql-hackers

From Merlin Moncure
Subject Re: json accessors
Date
Msg-id CAHyXU0zNtWbFdLDwDc_-7=dbRvTRNDtRvogQEO0hFWEfznzCRQ@mail.gmail.com
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In response to Re: json accessors  ("David E. Wheeler" <david@justatheory.com>)
List pgsql-hackers
On Wed, Dec 5, 2012 at 12:42 PM, David E. Wheeler <david@justatheory.com> wrote:
> On Dec 5, 2012, at 9:57 AM, Merlin Moncure <mmoncure@gmail.com> wrote:
>
>> Indexing large documents for fancy querying is a niche case but also
>> quite complex.  This isn't very well covered by xmlpath either btw --
>> I think for inspiration we should be looking at hstore.
>
> Agreed, although hstore, IIRC, does not support nesting.
>
>> That said, how would you do that?  The first thing that jumps into my
>> mind is to cut right to the chase:  Maybe the semantics could be
>> defined so that implement hackstack @> needle would reasonable cover
>> most cases.
>
> Yes.
>
>> So my takeaways are:
>> *) decomposition != precise searching.  andrew's api handles the
>> former and stands on it's own merits.
>
> Agreed.
>
>> *) xmlpath/jsonpath do searching (and decomposition) but are very
>> clunky from sql perspective and probably absolutely nogo in terms if
>> GIST/GIN.  postgres spiritually wants to do things via operators and
>> we should (if possible) at least consider that first
>
> I don't understand how xmlpath/jsonpath is not able to be implemented with operators.

yeah -- i phrased that badly -- by 'operators' I meant that on both
sides would be json document with absolute minimum fanciness such as
wildcards and predicate matches.  basically, 'overlaps' and
(especially) 'contains'.

merlin



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