For small queries, it does not matter much which approach you choose. But for large, complex queries, such 3-table join (especial Star Transformation) and/or large data set (millions of rows involved in large data warehouses), the performance will differ by order of magnitude, depending on how things are optimized. Steve -----Original Message----- From: haskell-cafe-bounces@haskell.org [mailto:haskell-cafe-bounces@haskell.org] On Behalf Of Peter Verswyvelen Subject: RE: [Haskell-cafe] Consensus about databases / serialization Yitz wrote:
My impression from some previous posts is that because of the high-level approach, it is difficult to control the precise SQL that is generated. In practice, you almost always have to do some tweaking that is at least DB-dependent, and often application dependent.
Can't the same be said regarding SQL itself? It sometimes needs tweaking. That's the problem with any high level abstraction no? Just like in Haskell you sometimes have to use strictness tweaks. Of course having an extra layer on top of SQL will make the tweaking more difficult :) Peter ------------------------------------------------------------------------------ Notice: This e-mail message, together with any attachments, contains information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station, New Jersey, USA 08889), and/or its affiliates (which may be known outside the United States as Merck Frosst, Merck Sharp & Dohme or MSD and in Japan, as Banyu - direct contact information for affiliates is available at http://www.merck.com/contact/contacts.html) that may be confidential, proprietary copyrighted and/or legally privileged. It is intended solely for the use of the individual or entity named on this message. If you are not the intended recipient, and have received this message in error, please notify us immediately by reply e-mail and then delete it from your system. ------------------------------------------------------------------------------