Re: Are we sufficiently clear that jsonb containment is nested?

On Wed, Jun 24, 2015 at 5:53 PM, Peter Geoghegan <pg(at)heroku(dot)com> wrote:
> I worry that "8.14.3. jsonb Containment and Existence" is not
> sufficiently clear in explaining that jsonb containment is nested.
> I've seen anecdata suggesting that this is unclear to users. We do
> say:
>
> """
> The general principle is that the contained object must match the
> containing object as to structure and data contents, possibly after
> discarding some non-matching array elements or object key/value pairs
> from the containing object.
> """
>
> I think that we could still do with an example showing *nested*
> containment, where many non-matching elements/pairs at each of several
> nesting levels are discarded. This could be back-patched to 9.4.
> Something roughly like the delicious sample data, where queries like
> the following are possible and useful:

I would be fine with adding a *compact* example of this kind to the
table that begins section 8.14.3. I probably would not back-patch it,
because the absence of that example is not an error in the
documentation, but I will not complain if someone else does.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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