Re: Relational Databases and Their Guts
Date: Sat, 21 Jun 2003 19:14:02 GMT
Message-ID: <_72Ja.65739$sm5.67991_at_rwcrnsc52.ops.asp.att.net>
"Todd Bandrowsky" <anakin_at_unitedsoftworks.com> wrote in message news:af3d9224.0306210602.294119ab_at_posting.google.com...
>
> That's what I'm trying to bumble my way into getting at. So, SQL
> Server, Oracle, MySQL are NOT RDMBS, because even though they are
> DBMS, they are not relational.
If one is speaking quite strictly, then yes. One might expect a fair bit of strictness in a .theory group.
> Now, let's see if I can get a better
> understanding of WHY SQL Server and Oracle are not true RDBMS.
> ...
> First off, the information in this link is wrong then, as it claims
> SQL implements Relational.
>
> http://wombat.doc.ic.ac.uk/foldoc/foldoc.cgi?relational+data+model
Strictly speaking, that is indeed incorrect.
> So called RDBMS are not relational because they do not implement some
> basic operators:
To my mind, the best reason to complain about SQL not being relational is that it allows duplicates. NULLs are pretty wacky, too.
> What is the ith thingy in an n tuple called?
'Round here, we generally think of elements of tuples as being named, not indexed. But maybe the word you want is "attribute."
Marshall Received on Sat Jun 21 2003 - 21:14:02 CEST