Re: Can I wrtie a function that has a BEFORE trigger that is notcolumn name dpendent? - Mailing list pgsql-general

From Adrian Klaver
Subject Re: Can I wrtie a function that has a BEFORE trigger that is notcolumn name dpendent?
Date
Msg-id 076f1857-e2d2-0d91-7520-cd2f2b57a2df@aklaver.com
Whole thread Raw
In response to Can I wrtie a function that has a BEFORE trigger that is not columnname dpendent?  (stan <stanb@panix.com>)
List pgsql-general
On 9/14/19 11:33 AM, stan wrote:
> I would like to write a generic function that I can place as a BEFORE trigger
> on several tables. It would do a max() on the column it was triggered for, and
> return(max + 1) unless max returns a NULL, in which case it would return one.
> 
> Yes, I know this  looks a lot like a sequence, but normally this value would
> be provided manually at row input time, I just want to allow for some
> automated updates.
> 
> The trick is hat the function needs to work for any numeric column I place it n
> as a trigger.
> 

What procedural language?

Triggers are placed on tables not columns so you will need some way of 
identifying the column(s) in the table. Trigger functions can take 
arguments even though they are not declared in the function creation. So 
that is one way of defining the column.

> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com



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