Re: Another Pizza Question

From: Dawn M. Wolthuis <>
Date: Tue, 13 Apr 2004 15:37:25 -0500
Message-ID: <c5hj2i$7vg$>

"Laconic2" <> wrote in message
> Dawn,
> I apologize if I unintentionally set a bear trap for you.
> I thought everybody would recognize this question as, "if there are
> toppings on a pizza are they a set or a list?"
> The PICK example shows them as a list. But is that inherent in toppings,
> or is that just the way PICK works?

The classifications of "parts" for the pizza are a set, while each such "field" of data would have a list -- whether the trivial list (corresponding to a null set), a single value in the list, or multiple values in a logically ordered list.

There are other ways to implement this, but doing so in this way shows up the structure of the data. An XML document could handily pass data to and from such a structure as is likely apparent. The multiple 1-M is a somewhat painful structure to implement in a relational database (not for those fluent in such, however) and also rather painful to prepare queries to retrieve data in the format the user wants to see it -- with a pizza and then each of the classifications with all valid values listed. Note that the second line for toppings is only related through parentage to the second cheese listed, so a single line in this 2D output from the database doesn't have that SQL/relational feel about it. You have to do somewhat unnatural things with SQL to get such output (IMO).

--dawn Received on Tue Apr 13 2004 - 22:37:25 CEST

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