Hi,
02.04.2018 15:04, Dmitry Dolgov пишет:
On 2 April 2018 at 12:36, PG Bug reporting form <noreply@postgresql.org> wrote:
The following bug has been logged on the website:
Bug reference: 15140
Logged by: Ivan Panchenko
Email address: i.panchenko@postgrespro.ru
PostgreSQL version: 10.3
Operating system: any
Description:
First. Impossible to create a nested structure for a path with more than one
new keys.
postgres => select jsonb_set('{}'::jsonb, array['x', 'y'],
to_jsonb(1::text), true);jsonb_set
-----------{}
(1 строка)
Expected {"x": { "y" : "1" }}
Second. Setting a NULL value nullifies the whole JSON
postgres=> select jsonb_set('{}'::jsonb, array['x'], null, true);jsonb_insert
--------------
(1 строка)
Expected { "x" : null }
As far as I remember, these are not really bugs, but documented behavior.
About the first one, here is [1]:
All the items of the path parameter of jsonb_set as well as jsonb_insert except the last item must be present in the target. If create_missing is false, all items of the path parameter of jsonb_set must be present. If these conditions are not met the target is returned unchanged.
Although I agree this can be confusing, and we may want to change this.
Yes, I think it would be good.
Now I see it in the documentation, but unfortunately, it is a separate note, which is not referenced from the main
jsonb_set description which says,
...with
new_value added if
create_missing is true ( default is
true) and the item designated by
path does not exist.
About the second one, `jsonb_set` is defined as a strict function, which means
`null` arguments will produce null as a result. To avoid this you can do:
=# select jsonb_set('{}'::jsonb, array['x'], 'null', true); jsonb_set ------------- {"x": null} (1 row)
1: https://www.postgresql.org/docs/devel/static/functions-json.html
Thanks for the workaround. Nevertheless, this behavior looks counter-intuitive, and I would vote for removing strictness from this function.
Regards,
Ivan