On 9/14/19 9:54 AM, Tom Lane wrote:
[snip
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.
Given that the UPDATE "*can* ... be set to fire only if certain columns are mentioned in the SET clause of the UPDATE statement", it logically follows that the default behavior is something else (for example, if the field value changes for whatever reason.
--
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