Subject: Adding funtions to postgresql (Not - )e: Please Help:
	PostgreSQL Query Optimizer
From: Hannu Krosing <hannu@skype.net>
To: Carlos Moreno <moreno@mochima.com>
Cc: pgsql-hackers@postgresql.org
In-Reply-To: <439CAE4D.2030208@mochima.com>
References: <Pine.LNX.4.61.0512111610320.4525@nsl-33.cse.iitb.ac.in>
	<200512111126.18566.josh@agliodbs.com>
	<Pine.LNX.4.61.0512120139080.6920@nsl-33.cse.iitb.ac.in>
	<439CAE4D.2030208@mochima.com>
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Date: Mon, 12 Dec 2005 01:45:26 +0200
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Ühel kenal päeval, P, 2005-12-11 kell 17:55, kirjutas Carlos Moreno:
> Hi,
> 
> I'm very new to this list -- I've been using and advocating PostgreSQL for
> no less than 4 or 5 years now, and have participated in some of the other
> mailing lists, but never on this one.
> 
> My question is (short version):  how would one go about adding a new
> (built-in) function to PostgreSQL?

Ask your question as a separate post, not as an answer t another
thread :)

> I'm interested in adding additional hash functions -- PG supports, as part
> of the built-in SQL functions, MD5 hashing.  So, for instance, I can simply
> type, at a psql console, the following:
> 
> select md5('abc');
> 
> My "feature request" (which again, I'd like to implement it myself) would
> be the ability to do:
> 
> select sha1('xyz'), sha256('etc');
> 
> (At least these two -- maybe for completeness it would be good to have
> sha224, 384, and 512, but I guess SHA1 and SHA-256 would be a very good
> and sound starting point)

Take a look at the pgcrypto contrib module (in src/contrib/pgcrypto )

Not only does it show how to add functions, but it also provides many of
the ones you need.

----------------
Hannu