Subject: surrogate key or not?
From: Markus Bertheau <twanger@bluetwanger.de>
To: pgsql-sql@postgresql.org
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Message-Id: <1090325769.3241.27.camel@dicaprio.akademie1.de>
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Date: Tue, 20 Jul 2004 14:16:09 +0200
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Hi,

I have a database that has types in them with unique names. These types
are referenced from other tables through a surrogate integer key. I'm
now wondering if I should eliminate that surrogate key and just use the
name as the primary key. Afaiu, surrogate keys are primarily there to
make joining tables or otherwise searching for a record faster, because
it's faster to compare two integers than it is to compare two strings.

Now when I want to search for a type in types or another table that
references types(type_id), under what circumstances is it advisable to
have a surrogate integer key and not use the unique type name? Is
searching for an integer as fast as is searching for a string when both
have an index? How many records in the type table do I need to make a
surrogate key a not unsignificantly faster way to retrieve a row? What
about joins? Are these the right questions?

Thanks.

-- 
Markus Bertheau <twanger@bluetwanger.de>