Re: The MySQL/PHP pair

Dawn M. Wolthuis wrote:

>
> What is the problem if I want to persist the proposition:
>
> Person
> Bob Smith has e-mail addresses of bob_at_aol.com and bobsmith_at_msn.com
>
> It seems to me that there are advantages to modeling this predicate in
> this way rather than modeling it with the statements
>
> Email
> The Person with ID 12345 has an e-mail address of bob_at_aol.com
> The Person with ID 12345 has an e-mail address of bobsmith_at_msn.com
>
> Person
> The Person with ID 12345 is Bob Smith.
>
> Conceptually a single statement is clearer. If the database has some
> reason of spitting our one predicate into three prior to storing it and
> before retrieving it, so be it, but logically why not handle it with the
> single statement?
>

This comes down to the basic ideas of decomposition and composition. How far do I decompose the information? There is deadline pressure to avoid decomposition because it costs time and money to decompose something that you are just going to put back together again.

However, experience seems to suggest very strongly, and here I can only quote experience, that the strongest designs (those that do not require me to work an emergency on Christmas) begin with complete atomistic decomposition, going down to the level below where there is nought.

...which brings us back nicely to 1NF. Classical 1NF can be thought of as complete decomposition.

-- 
Kenneth Downs
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