It looks like I do not know enough about the JSON type and I was treating
it always like an object with keys and values. You are absolutely correct,
now I see that I can really:
db=# select '2'::jsonb;
jsonb
-------
2
(1 row)
Which explains everything.
Cheers,
2016-10-06 15:47 GMT+03:00 Tom Lane <tgl@sss.pgh.pa.us>:
> Kouber Saparev <kouber@gmail.com> writes:
> > Okay, I also saw in the source code that it is looking for an
> _json-object_
> > (whatever that means) and is throwing that error otherwise. The thing is
> -
> > in my perception the string 'null' , being valid json(b), should also be
> > treated as valid _json-object_, isn't it?
>
> No. A JSON "object" is something with field names and values, like a
> Perl hash. JSON also has scalars and arrays; those are JSON values,
> but not JSON objects. 'null' is a scalar, I think, although for some
> purposes it might be better to view it as a fourth primitive kind of
> JSON value.
>
> jsonb_each_text() needs to work on a JSON object because otherwise its
> return convention of returning a set of field names and values makes
> no sense. What would you imagine jsonb_each_text('2'::jsonb) ought
> to do? Similarly, there's not really any sensible interpretation
> of jsonb_each_text('null'::jsonb).
>
> > ... I felt its an
> > inconsistency in PostgreSQL itself.
>
> The distinction between objects and other kinds of JSON values is
> drawn in the JSON standard; we did not make it up. See
> http://rfc7159.net/rfc7159
>
> regards, tom lane
>