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Re: Database question ?

From: --CELKO-- <jcelko212_at_earthlink.net>
Date: 13 Aug 2004 19:05:53 -0700
Message-ID: <18c7b3c2.0408131805.486c47cd@posting.google.com>


>> Q: How is data actually stored?

  1. The relational model model does not say. Am I missing something? <<

You got it!! I can think of 4-5 SQL engines whose internal file designs are absolutely nothing in common.

Teradata uses hashing and parallelism; An entire Nucleus database is one compressed bit vector space; SQL Server is still based on contigous physical storage; Sybase SQL Anywhere uses pointer chains from a PK to all the FK that reference it; Ingres has over a dozen different index types; Want to look at concurrency control in InterBase?

The beauty of an abstract language spec is that you can do it anyway you want and the same SQL can run on all of them. This assumes that the vendor does not give you an incomplete product or proprietary carp, of course. Received on Fri Aug 13 2004 - 21:05:53 CDT

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