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Re: Named Mistakes and Questionable Practices

From: -CELKO- <jcelko212_at_earthlink.net>
Date: 10 Jun 2006 16:19:44 -0700
Message-ID: <1149981583.996100.165640@y43g2000cwc.googlegroups.com>


>> I presume this is considered a mistake only because of SQL allowing duplicate "rows". In the real RM, no such mistake is possible. <<

No, we would have Dr. Codd's "Degree of Duplication" operator that nobody mentions. This is how he handled dups in RM II. At least you can avoid dups in base tables in SQL via constraints and in results via SELECT DISTINCT. Teradata used to disallow duplicate rows in its early versions, but lost out to Standard SQL. My wish is that we had put in a [CREATE | DECLARE] FILE <name> (<column list>) construct for the non-tables. But SQL was built on the existing indexed file systems of the day, and we are stuck with the family legacy (aka "family curse"). Received on Sat Jun 10 2006 - 18:19:44 CDT

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