Re: Extending my question. Was: The relational model and relational algebra - why did SQL become the industry standard?

From: Jan Hidders <>
Date: 13 Feb 2003 14:17:44 +0100
Message-ID: <>

Lauri Pietarinen wrote:
>Jan Hidders wrote:
>>There are two separate questions here:
>>1. Do we want duplicates in the data model, i.e., in the original relations
>> and the results of queries?
>>2. Do we want duplicates in intermediate results?
>>I'm not completely sure what their answer to 1. is but I suspect it is
>>something like "probably not".
>That's not the impression I get from Date's article (see part II), but I
>have not read the book.

The book is agnostic on this issue. It's starting point is that you want to build an SQL database (and so there are duplicates in your results) and then explains how you should do that.

  • Jan Hidders
Received on Thu Feb 13 2003 - 14:17:44 CET

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