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help / color / mirror / Atom feedFrom: David G. Johnston <[email protected]>
To: Josh Silver <[email protected]>
Cc: Pg Docs <[email protected]>
Subject: Re: Clarification of triggers with 'OF column_name' in 'Overview of Trigger Behavior'
Date: Mon, 2 May 2022 18:55:09 -0700
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On Mon, May 2, 2022 at 6:33 PM Josh Silver <[email protected]> wrote:
>
> and the 'Overview of Trigger Behavior pages says of before triggers
>
>> In row-level triggers the WHEN condition can examine the old and/or new
>> values of columns of the row. (Statement-level triggers can also have
>> WHEN conditions, although the feature is not so useful for them.) In a
>> BEFORE trigger, the WHEN condition is evaluated just before the function
>> is or would be executed, so using WHEN is not materially different from
>> testing the same condition at the beginning of the trigger function.
>
>
> but does not even mention column specific triggers by name.
>
>
The previous paragraph reads in part:
"If more than one trigger is defined for the same event on the same
relation, the triggers will be fired in alphabetical order by trigger name."
I'll say that we don't provide a granular definition of what an "event" is
here - namely the "INSERT/UPDATE/DELETE/SELECT + any column limitation".
So, it is covered if you understand the column aspect is rolled into
"trigger event".
David J.
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To: [email protected]
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Subject: Re: Clarification of triggers with 'OF column_name' in 'Overview of Trigger Behavior'
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