Re: jsonb_delete with arrays

On Tue, Jan 17, 2017 at 8:25 AM, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>
wrote:

> On Sun, Dec 18, 2016 at 1:27 AM, Dmitry Dolgov <9erthalion6(at)gmail(dot)com>
> wrote:
> > Speaking about implementation of `jsonb_delete_array` - it's fine, but I
> > would like to suggest two modifications:
> >
> > * create a separate helper function for jsonb delete operation, to use
> it in
> > both `jsonb_delete` and `jsonb_delete_array`. It will help to concentrate
> > related logic in one place.
>
> I am not sure that it is much a win as the code loses readability for
> a minimal refactoring. What would have been nice is to group as well
> jsonb_delete_idx but handling of the element deletion is really
> different there.
>

I agree with that. I agree with investigating it as an option, but I think
the lost readability is worse.

>
> > * use variadic arguments for `jsonb_delete_array`. For rare cases, when
> > someone decides to use this function directly instead of corresponding
> > operator. It will be more consistent with `jsonb_delete` from my point of
> > view, because it's transition from `jsonb_delete(data, 'key')` to
> > `jsonb_delete(data, 'key1', 'key2')` is more smooth, than to
> > `jsonb_delete(data, '{key1, key2}')`.
>
> That's a good idea.
>

I can see the point of that. In the particular usecase I built it for
originally though, the list of keys came from the application, in which
case binding them as an array was a lot more efficient (so as not to
require a whole lot of different prepared statements, one for each number
of parameters). But that should be workaround-able using the VARIADIC
keyword in the caller. Or by just using the operator.

> > I've attached a patch with these modifications. What do you think?
>
> Looking at both patches proposed, documentation is still missing in
> the list of jsonb operators as '-' is missing for arrays. I am marking
> this patch as waiting on author for now.
>

Added in updated patch. Do you see that as enough, or do we need it in some
more places in the docs as well?

--
Magnus Hagander
Me: http://www.hagander.net/
Work: http://www.redpill-linpro.com/