Re: Slick way to update multiple tables.

[Paul Jungwirth <pj@xxxxxxxxxxxxxxxxxxxxxxxx>]

On 4/1/21 11:54 AM, Michael Lewis wrote:
> postgresql.org/docs/current/sql-createview.html 
> <http://postgresql.org/docs/current/sql-createview.html>
>
> My apologies. It seems INSTEAD OF triggers are required to implement 
> updates across multiple tables. I thought not if all were simple joins. 
> My mistake.

Even with INSTEAD OF triggers, if you use a view then I suppose you 
would be forced to update some of the records more often that necessary? 
(Unless your tables are 1-to-1-to-1 of course.) Or if there is some 
trick to avoid that I'd be curious to know about it.

Here is something I've done in the past:

WITH
update1(ok) AS (
  UPDATE foo SET ... WHERE ...
  RETURNING 'ok'
),
update2(ok) AS (
  UPDATE bar SET ... WHERE ...
  RETURNING 'ok'
),
update3(ok) AS (
  UPDATE baz SET ... WHERE ...
  RETURNING 'ok'
)
SELECT ok FROM update1
UNION ALL
SELECT ok FROM update2
UNION ALL
SELECT ok FROM update3
;

You could even select different messages from each update if you want to 
know how many rows you touched in each table.

--
Paul              ~{:-)
pj@xxxxxxxxxxxxxxxxxxxxxxxx