Re: trigger - dynamic WHERE clause

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
To: Tarlika Elisabeth Schmitz <postgresql3(at)numerixtechnology(dot)de>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: trigger - dynamic WHERE clause
Date: 2011-05-31 04:09:18
Message-ID: BANLkTim5R_FVHvm9EEZ9NcRMqgCzXsD3wg@mail.gmail.com
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2011/5/31 Tarlika Elisabeth Schmitz <postgresql3(at)numerixtechnology(dot)de>:
> On Mon, 30 May 2011 11:02:34 +0200
> Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
>
>>> 2) I took from your blog entry
>>> (http://okbob.blogspot.com/2008/06/execute-using-feature-in-postgresql-84.html)
>>> that it is good practice to use EXECUTE USING.
>>> Well, there's no danger of SQL injection as this particular DB runs
>>> on an internal network. However, I am wondering whether EXECUTE
>>> USING has a performance advantage?
>>>
>>
>>You newer know where or who is attacker :)
>>The performance is very similar now - the most slow part is generating
>>of execution plan - not IO operations.
>
> I have converted my generic trigger to use EXECUTE ... USING.
>
> I need to convert all NEW values to a text array, retaining their
> ordinal position.
> avals(hstore(NEW)) doesn't seem to do that:
>
> NEW: (5,name5,1000,,,2)
> avals(hstore(NEW)):  {5,name5,2,1000,NULL,NULL}
>
> The best I can come up with is a JOIN with information_schema.columns.

jup

it should be relative expensive (slow). If you need a generic triggers
use different PL instead. I can not to know what requests you have to
solve. But try to look on PLPerl or PLPython. Generic triggers can be
developed there with less work.

Regards

Pavel

>
> --
>
> Best Regards,
> Tarlika Elisabeth Schmitz
>
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