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Re: A question about relationship

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On Tuesday, 11 February 2014 20:54:38 UTC, Erland Sommarskog  wrote:
> Tony Johansson (johansson.andersson@telia.com) writes:
> > Yes a customer without order sounds ok
> > But order without customer is incorrect.
> 
> I would say that it depends on the business rules. :-) But, yes, it
> would be a bit peculiar.
> 
> In Northwind CustomerID is nullable, although there is no such order 
> in the data. Unfortunately, Northwind leaves a whole lot desired when it 
> comes to nullability, indexes etc.

I don't remember if I ever worked in the Northwind database.
(My actual training was some of the authentic courses for 
SQL Server 7.)  So I don't know if some of its features are
included intentionally to attract criticism for extra credit
in class - you know, spot the little design mistakes.  
That can be good practice for real work.  Or if it's just
not particularly well done.

It bothers me a little that most database courses I've seen
are about developing yet another new customer and order database 
for a business, when that's the last thing that the world needs - 
unless you have an amazing new idea about how to do it.  
Maybe that's what they're looking for?

But I suppose that (1) it's really about understanding how
data table relationships work and how to use SQL to talk to
your database, and (2) it's businessy.  Whereas a course 
based around recording a kindergarten class's personal 
achievements, family relationships and friend and unfriendships, 
allergies, and favourite colours, TV shows, etc., for instance, 
might be too "out there".  Although curiously, I run the 
database for - :-)

Also...  I /actually/ work in a room of around 30 men 
and, as far as I've noticed, 1 woman.  That's not right.
I should have my own office.

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Thread

A question about relationship "Tony Johansson" <johansson.andersson@telia.com> - 2014-02-10 15:18 +0100
  Re: A question about relationship Erland Sommarskog <esquel@sommarskog.se> - 2014-02-10 23:39 +0100
    Re: A question about relationship "Tony Johansson" <johansson.andersson@telia.com> - 2014-02-11 15:39 +0100
      Re: A question about relationship Ross Presser <rpresser@gmail.com> - 2014-02-11 07:11 -0800
        Re: A question about relationship bradbury9 <ray.bradbury9@gmail.com> - 2014-02-11 08:43 -0800
          Re: A question about relationship Ross Presser <rpresser@gmail.com> - 2014-02-11 09:33 -0800
        Re: A question about relationship Lennart Jonsson <erik.lennart.jonsson@gmail.com> - 2014-02-11 18:01 +0100
      Re: A question about relationship Erland Sommarskog <esquel@sommarskog.se> - 2014-02-11 21:54 +0100
        Re: A question about relationship rja.carnegie@gmail.com - 2014-02-11 13:49 -0800
          Re: A question about relationship Erland Sommarskog <esquel@sommarskog.se> - 2014-02-11 23:23 +0100

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