NYCPHP Meetup

[Kenneth Downs]

> inforequest wrote:
>
>>I guess I am just underlining that the initial question of modeling data
>>vs. modeling system or application requirements does not always
>>encompass database design. In my experience, one must always consider
>>the platform and the application from the start, and almost always
>>re-design the database around platform factors known later. Yeah, lots
>>of "extra work".
>>
>>One plus for agile software development http://agilemanifesto.org/ and
>>an underline of the value of "ben there, done that".
>>
>>
> Great link, and all in all this whole discussion is very helpful -- I've
> been way gone on normalization and never really considered the impact
> that it could have on my apps.

Normalization can have a huge impact on your apps -- it can reduce many
data entry errors and eliminate others entirely.  That is its purpose. 
Without normalization all of the time you spend supporting a slow app will
be spent fixing errors in bad data.

But querying data is a different thing.  If you have known common queries
that aggregate and join data, then by all means create some summary system
that is, hopefully, automatic and guaranteed to be right.  This is not
really denormalization, though the relational theorist will argue it is. 
What it is in fact is the creation of derived tables based on normalized
tables.

But anyway, normalize the tables users can directly modify, and use
summaries derived from those normalized tables.  Then you get accurate
data coming in and that makes for accurate summaries.



>
> - Allen
>
> --
> Allen Shaw
> Polymer (http://polymerdb.org)
>
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-- 
Kenneth Downs
Secure Data Software
631-379-0010
ken at secdat.com
PO Box 708
East Setauket, NY 11733