Re: Base Normal Form

In message <1121202113.304417.98600_at_z14g2000cwz.googlegroups.com>, dawn <dawnwolthuis_at_gmail.com> writes
>Eric Junkermann wrote:
>> In message <1121162228.113616.139680_at_g14g2000cwa.googlegroups.com>, dawn
>> <dawnwolthuis_at_gmail.com> writes
>> [snip]
>> >> Same here. (Holistic this side of the pond)
>> >
>> >Terrific! I'm forever reading statements about how we must be sure to
>> >model the data separate from how they will be used.
>> >
>> >--dawn
>> >
>>
>> You are all programmers at heart,
>
>I'll accept that.
>
>> you are tricked by your need to
>> process data into believing that it is yours.
>
>but not that. What I will accept is that changes will be required
[snip]
>our design needs to accomodate this sharing of "memory".

and if the shared "memory" is the wrong "shape", so that our path from "given" to "required" for the new application is too complicated, we will pay for it somehow. What I am saying is that if you use data in a certain way you will tend to bundle it in that way, even if you are trying to be flexible, so the best bundle is an open bundle, which will have different ways in.

[snip]
>There are tradeoffs to constraining the length of a field, for example,
>and allowing any length.

but this is a physical issue, an implementation issue, not a design issue, the logical data design does not care.

[snip]

>Do you really think that most ETL is done because data are NOT modeled
>relationally?

Did I mention relational?

ETL happens because data is the wrong "shape", the type of system it is stored in is not the main problem. Given similar needs, the ones that do the least ETL are those with the most flexible data design.

Maybe I shouldn't have dragged ETL in, but my main point remains that data independence is a good thing - which is where Codd came in, whether you like his answer or not.

Regards,

Eric

-- 
Eric Junkermann