Re: The fable of DEMETRIUS, CONSTRAINTICUS, and AUTOMATICUS

From: Kenneth Downs <firstinit.lastname_at_lastnameplusfam.net>
Date: Sat, 23 Oct 2004 21:12:36 -0400
Message-ID: <4ivelc.ivc.ln@mercury.downsfam.net>

Marshall Spight wrote:

> "Kenneth Downs" <firstinit.lastname_at_lastnameplusfam.net> wrote in message
> news:jma9lc.ner.ln_at_mercury.downsfam.net...

>>
>> Code is recipes.  They tell you what to do and you store them in a filing
>> cabinet.  Data is food, like flour and pies, you store them in the pantry
>> and the refrigerator.  When this distinction is not understood, you get
>> paper in the fridge and flour in the filing cabinet.

>
> True, as far as it goes, but we can also consider code to be data, and
> data to be code. Any bytecode system is a formal mechanism for specifying
> code as data; the lambda calculus and Church numerals let us specify
> data as code.
>
> I think there's not much value to considering data to be code, but I
> do see value in viewing code as data, when appropriate.

I would contend that it is never appropriate to consider SQL code to be data, it simply is not.

Code is data when you get down to certain levels, yes, like bytecode, and food is paper when you get down to carbon and nitrogen. But again I contend that when implementing database systems or meta-data systems there is only madness in confounding code and data.

>
>

>> Or another example.  I can do this:
>>
>> CREATE VIEW new_columns AS
>> SELECT column_id FROM dd_columns
>>   WHERE column_id_existing IS NULL
>>
>> but I cannot do this:
>>
>> SELECT features FROM file:///BigBunchOfDDL.SQL
>>   WHERE Columns ARE Numeric
>>     AND columns HAVE Constraints

>
> Why not? The where clause at least is perfectly consistent with
> querying the catalog. (I'm not sure I understand the FROM part.)
>

the FROM clause is a disk file full of SQL statements, or perhaps if you like Java or C#. You cannot query this information with SQL, because it is not in tables. Moreover, it is of a fundamentally different nature and does not even contain the same kind of information.

-- 
Kenneth Downs
Use first initial plus last name at last name plus literal "fam.net" to
email me

Received on Sat Oct 23 2004 - 20:12:36 CDT