Re: Auto-updated fields - Mailing list pgsql-hackers

From Tino Wildenhain
Subject Re: Auto-updated fields
Date
Msg-id 4822811E.4020800@wildenhain.de
Whole thread Raw
In response to Auto-updated fields  (David Fetter <david@fetter.org>)
Responses Re: Auto-updated fields  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: Auto-updated fields  (Robert Treat <xzilla@users.sourceforge.net>)
List pgsql-hackers
David Fetter wrote:
> Folks,
> 
> A co-worker pointed out to me that MySQL has a feature that, properly
> implemented and maybe extended, could be handy, namely what MySQL
> calls a "timestamp" field, so here's a proposal:
> 
> 1.  Create a generic (possibly overloaded) trigger function, bundled
> with PostgreSQL, which sets a field to some value.  For example, a
> timestamptz version might set the field to now().
> 
> 2.  Have some kind of pre-processing of CREATE and ALTER statements on
> tables which would attach the above function to the field at hand,
> something like:
> 
> CREATE TABLE foo(
>     last_updated TIMESTAMPTZ_UPDATED(),
>     ...
> );
> 
> which would turn last_updated into a TIMESTAMPTZ with the expected
> behavior on UPDATEs.
> 
> What do folks think of this idea?

Having the pre defined triggers at hand could be useful, especially
for people not writing triggers so often to get used to it but I'm
really not happy with the idea of magic preprocessing.

I guess this is commonly used with timestamp fields so why not
include a receipe to the docs under examples for timestamp which
shows how to create and use a trigger?

I may be wrong but my feeling is, not to much weirdness in the core
please :) (I guess mysql had it because of lacking triggers and stuff
for a long time?)

T.


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