Re: json_to_record Example

On Sat, Jun 2, 2018 at 03:23:32PM +0200, Yousof Shaladi wrote:
> Hi,
>
> Form my side I definitely agree with what you say and added. I think the
> example makes it more clear as we have an example table used.
>
> Nothing to add from my side here.

Patch applied back through 9.4. Thanks.

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>
> Best regards,
>
>
> On Sat, May 26, 2018 at 5:03 PM Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>
> On Mon, May  7, 2018 at 06:14:02PM +0000, PG Doc comments form wrote:
> > The following documentation comment has been logged on the website:
> >
> > Page: https://www.postgresql.org/docs/10/static/functions-json.html
> > Description:
> >
> > Hi team,
> >
> > I had the following issue when going through your
> > https://www.postgresql.org/docs/current/static/functions-json.html docs.
> >
> > Looking at the json_to_record example it took me quite a while that it is
> > not possible to put the json_to_record function right after the the from
> > clause but instead I would need to put the tables name in front, then use
> > the json_to_record function. Then put the column definitions behind it
> and
> > in the SELECT clause I need to query the columns using the alias. As you
> use
> > a * in your examples, I assumed that json_to_record returns all values
> found
> > in the json argument of that function.
> >
> > As an idea I would suggest to provide a sample json which contains
> key-value
> > pairs as well as arrays and use this for the whole examples as someone
> would
> > rather not query a json written by hand.
> >
> > Thank you very much and keep up the good work! I hope you understand and
> > like my suggestion!
>
> I think you have a good point.  I was confused too and it took me a
> while to get it straight.  The simplest example I could create is:
>
>         CREATE TABLE test(x INT, y JSONB);
>
>         INSERT INTO test VALUES (DEFAULT, '{"a":2,"b":[1,2,3],"c":
> [1,2,3],"e":"bar","r": {"a": 123, "b": "a b c"}}');
>
>         SELECT x.* FROM test, jsonb_to_record(y) AS x(a int, b text, c int
> [], d text);
>          a |     b     |    c    | d
>         ---+-----------+---------+---
>          2 | [1, 2, 3] | {1,2,3} |
>
> While we could add this to the docs, I prefer some text that explains
> how to use this, and perhaps why.
>
> The benefits of jsonb_to_record and friends compared to typical ->
> JSON[B] indexing was outlined in this thread, and I am CC'ing the author
> in this thread:
>
>         https://www.postgresql.org/message-id/flat/
> C3E7372D-153D-4276-8DB5-0D232ECD91E4%40gmail.com
>
> I have developed the attached doc patch which explains how to use
> jsonb_to_record using a lateral reference (though the LATERAL keyword is
> optional for function calls in Postgres), and a suggestion of the
> performance benefits of using it.  I feel text is really required to
> accomplish all this, rather than an example.
>
> Comments?
>
> --
>   Bruce Momjian  <bruce(at)momjian(dot)us>        http://momjian.us
>   EnterpriseDB                             http://enterprisedb.com
>
> + As you are, so once was I.  As I am, so you will be. +
> +                      Ancient Roman grave inscription +
>
> --
>
> Yousof Sagr Shaladi
>
> Services Engineering
>
> Denodo Technologies
>
> +49 (0) 89 599 904 50
>
> yshaladi(at)denodo(dot)com
>
> www.denodo.com
>

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ As you are, so once was I. As I am, so you will be. +
+ Ancient Roman grave inscription +