Adrian Klaver <adrian.klaver@aklaver.com> writes:
> On 9/13/19 8:07 PM, Judy Loomis wrote:
>> At the very least that note about this behavior should be highlighted,
>> probably on the Trigger Behavior page and not buried in a bunch of notes
>> on the Create Trigger page.
> I know this after the fact. Still, as a general rule the best place to
> start when learning about a command is on it's respective page under here:
> https://www.postgresql.org/docs/11/sql-commands.html
> Further I usually go to the Notes after reading the synopsis, as Notes
> is where the exceptions to the rules and gotchas are called out.
The only mention of this feature in 38.1 "Overview of Trigger Behavior"
is
UPDATE triggers can moreover be set to fire only if certain columns
are mentioned in the SET clause of the UPDATE statement.
which seems to me to be plenty specific enough --- it is carefully
*not* saying that the trigger will fire if the column changes value.
The CREATE TRIGGER man page never says that, either.
regards, tom lane