Re: The MySQL/PHP pair

Dawn M. Wolthuis wrote:

> OK, I didn't understand what you were referring to as "adding automation".
> It sounds like you are referring to virtual and/or materialized
> user-defined
> data, virtual fields, derived data, UDFs, stored procedures, etc. These
> are
> all automated by way of "code" specified in attributes as metadata,
> right? So your "USER-SUPPLIED" columns are supplied with the metadata
> having no "code" other than name, size, type, desc, or whatever, where
> your "AUTOMATED" have additional "metadata" to derive the value from
> whereever, rather than requiring that the data be stored directly
> (maybe?).
>

We are pretty much on the same page on all points except one. The specification of automated columns must not contain code, they must be scalar. The two working points to define scalar (or atomic) in this context are:

1. Must not require evaluation according to the rules of any programming language.
2. Must not require parsing by the engine built to use it.

So if you have some automatic view builder working with a data dictionary, the formula for Extended_Price cannot be the expression "price * qty", it must be the scalar values "MULT","PRICE","QTY" with the assumption that all columns are in the same table. In the same vein, an aggregate for an order total might be "SUM","ORDER_LINES","LINE_FINAL_AMT".

...and so we return to assembly language ;-)

-- 
Kenneth Downs
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