Re: the relational model of data objects *and* program objects

From: Kenneth Downs <knode.wants.this_at_see.sigblock>
Date: Fri, 15 Apr 2005 08:50:19 -0400
Message-Id: <cvp4j2-gsb.ln1@pluto.downsfam.net>

mountain man wrote:

> "Kenneth Downs" <knode.wants.this_at_see.sigblock> wrote in message
> news:60l3j2-g8s.ln1_at_pluto.downsfam.net...

>> mountain man wrote:
>>
>>>> So first we need to identify such dual things in programs, data and
>>>> processes.
>>>
>>> I have thought about this, and concluded that the greatest
>>> (and single most cost-incurring expense) related to database
>>> systems is RE-definition of data ---- once in the database,
>>> and again in the code (wherever the code may actually reside)
>>>
>>
>> ...and once again in the next layer of the code, as in:
>>
>> 1)  db layer
>> 2)  web service layer
>> 3)  browser layer
>>
>> This is why the One True Data Dictionary must exist outside of all of
>> them,
>> and be used to implement all of them.   If the spec is both
>> machine-readable and human-readable, mores the better.

>
>
> Another alternative is to have the data dictionary defined
> within the database systems software once and definitively
> and all other software layers reference this. Of course the
> db layer could publish this into other layers.
>

I've tried this in at least two forms and decided it was better to "cache" a copy of the dd in the web layer in its own language. Makes for far simpler layer-boundary code. The delta-dd occurs only during a build, in fact a build defines the delta-dd event, so at that point you put the data into a form that is appropriate for the other layers and can safely leave it there unaltered until the next build.

-- 
Kenneth Downs
Secure Data Software, Inc.
(Ken)nneth@(Sec)ure(Dat)a(.com)

Received on Fri Apr 15 2005 - 07:50:19 CDT