Home Page for the TeradataForum

Archives of the TeradataForum

Message Posted: Fri, 27 Jan 2006 @ 21:13:52 GMT

  <Prev Next>   <<First <Prev Next> Last>>  

Subj:   Re: Erwin is not mi amigo again...
From:   Victor Sokovin

  I agree that MULTISET tables violates Relational theory.  

It's been a long time since I looked at that "theory". I do remember, though, that most of what I read looked like description of "best practices", not a clear mathematical theory.

A pure mathematical part is too abstract in nature and it is very far from what we see in real-life RDBMS. RDBMS are just based on the "best practices" part, which ensures their more-or-less compatibility. In my opinion, this is the most important historical contribution of the theory. It had introduced a common language long before ANSI et al. But after that I don't see anything of practical value. All RDBMS are internally built on different, vendor specific algorithms.

I, for one, am not aware of RDBMS which does _not_ support multiset tables. They just simply call them tables. "Multiset" term was probably Teradata's invention? The concept itself is very common across vendors.



  <Prev Next>   <<First <Prev Next> Last>>  
  Top Home Privacy Feedback  
Copyright for the TeradataForum (TDATA-L), Manta BlueSky    
Copyright 2016 - All Rights Reserved    
Last Modified: 28 Jun 2020