it don't mean a thing if it don't mean a thing (was: Something with wisdom and OO and RDBMS)
Date: Tue, 13 Jun 2006 20:36:18 +0200
Robert Martin wrote:
> erk said:
>> Robert Martin wrote: >>> However, the data cannot remain in the DBMS for its entire lifetime. >>> The RNA has to leave the nucleus and get out into the cytolasm to do >>> it's work. And out there in the cytoplasm the integrity of the data is >>> no longer the responsibility of the DBMS. >> >> Both the genetic and the distribution network analogies are so bad as >> to be useless. Data and information do not "move" in any meaningful way >> (just as systems are not "constructed" in the same sense as either a >> car or a building).
> You and I have a very different view of how software systems are built.
> In my world the data moves from magnetic domains on the disk to electric
> fields in MOSFETS.
What moves there is something electrical - voltage levels, currents, not even bits & bytes, definitely /not/ data in the sense the word is used in the context of databases: meaningful data to the end-user.
These electrical thingies carry bits - by interpretation.
These bits in turn may carry data.
At the level of magnetics in a
computer no data is moving.
> From that point the data moves from one set of
> MOSFETS to another, but changes form many times, until it gets to the
> form of an array of tuples that corresponds to some programming language
There is really no 'until' here.
The 'array of tuples' at all times corresponds to a vast collection of currents/voltages, but we use the abstraction of 'array of tuples' of the programming language in order not to have to be aware of those electrical/magnetical thingies all the time.
> From that point it moves yet again to yet other MOSFETS
> under the control of the application and takes forms that are more
> convenieht for the application programmer to maniuplate.
This "takes forms" never actually happens. We share a sophisticated belief system that makes us think that we are manipulating bits and bytes while we are actually manipulating currents and phase shifts.
> In the midst
> of all this the data may move from MOSFETS to voltage potentials along a
> wire, or frequency phase shifts along radio waves.
> To paraphrase Gallileo (appochraphal) "And yet the data moves."
> This is not a frivolous argument.
The argument depends on magical transformation
moments: from data to electromagnetic
phenomena and vv. IMO these moments are historical (the growth of the shared belief system), but non-existent in the universe of the application and the database. The data and the currents exist in their own realm at the same time.
[snip control] Received on Tue Jun 13 2006 - 20:36:18 CEST