On 2019-10-20 13:20:23 -0700, Steven Pousty wrote:
> I would think though that raising an exception is better than a default
> behavior which deletes data.
> As an app dev I am quite used to all sorts of "APIs" throwing exceptions and
> have learned to deal with them.
> 
> This is my way of saying that raising an exception is an improvement over the
> current situation. May not be the "best" solution but definitely an
> improvement.

I somewhat disagree. SQL isn't in general a language which uses
exceptions a lot. It does have the value NULL to mean "unknown", and
generally unknown combined with something else results in an unknown
value again:

    % psql wds
    Null display is "(∅)".
    Line style is unicode.
    Border style is 2.
    Unicode border line style is "double".
    Timing is on.
    Expanded display is used automatically.
    psql (11.5 (Ubuntu 11.5-3.pgdg18.04+1))
    Type "help" for help.

    wds=> select 4 + NULL;
    ╔══════════╗
    ║ ?column? ║
    ╟──────────╢
    ║      (∅) ║
    ╚══════════╝
    (1 row)

    Time: 0.924 ms
    wds=> select replace('steven', 'e', NULL);
    ╔═════════╗
    ║ replace ║
    ╟─────────╢
    ║ (∅)     ║
    ╚═════════╝
    (1 row)

    Time: 0.918 ms

Throwing an exception for a pure function seems "un-SQLy" to me. In
particular, jsonb_set does something similar for json values as replace
does for strings, so it should behave similarly.

        hp

-- 
   _  | Peter J. Holzer    | we build much bigger, better disasters now
|_|_) |                    | because we have much more sophisticated
| |   | h...@hjp.at         | management tools.
__/   | http://www.hjp.at/ | -- Ross Anderson <https://www.edge.org/>

Attachment: signature.asc
Description: PGP signature

Reply via email to