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relational reasoning -- why two tables and not one?

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  #31  
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Bob Badour
 
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Default Re: relational reasoning -- why two tables and not one? - 10-17-2009 , 10:43 PM






Gene Wirchenko wrote:

Quote:
On Fri, 16 Oct 2009 22:39:56 -0300, Bob Badour
bbadour (AT) pei (DOT) sympatico.ca> wrote:

Gene Wirchenko wrote:

On Thu, 15 Oct 2009 22:43:15 -0300, Bob Badour
bbadour (AT) pei (DOT) sympatico.ca> wrote:

[snip]

That's certainly one type of mysticism. In this case, I think we have
someone acting more like Alice with Humpty Dumpty. The name "donation"
means exactly what the person who applied it to a table meant at the time.

More like Humpty Dumpty:
"'When I use a word,' Humpty Dumpty said in rather a scornful tone,
'it means just what I choose it to mean—neither more nor less.'" --
"Through the Lookingglass"

I disagree. The person who created the donations table acted exactly
^^^^^^^^^^^ ^^^^^^^^^^^^^^
like Humpty. The name means exactly what he meant when he applied it to
^^^^^^^^^^^^
the table. That person isn't here that we know of.

??? You disagree, but then you state my case.
I disagree because the Humpty person is neither here nor practising any
sort of mysticism I can discern. That person has a single relation with
a single name. The name does not magically cause a need for a second
relation. The Alice character on the other hand...

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  #32  
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Philipp Post
 
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Default Re: relational reasoning -- why two tables and not one? - 10-19-2009 , 05:09 AM






Lawpoop,

Quote:
A couple folks ( myself included ) thought that there should be at least two tables -- 'donors' and 'donations' . But the poster argued that no, there would never be a holiday fund drive appeal sent out to all donors, or a year-end statement, or anything of that sort. So a single table would suffice.
From your description it seems to me that the poster would like to use
something quite simple, such as a wizard-generated bulk mailing which
for example is available in MS Word. Usually such data source is a
single table in MS Word, MS Excel or any database query on MS Access
or superior systems.

I agree that the single table solution will not scale up well, is not
properly normalized, but as you stated the OP was not interested in
that and apparently had no need for it.

I would therefore vote for that beeing a misunderstanding of some
kind.

brgds

Philipp Post

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  #33  
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Roy Hann
 
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Default Re: relational reasoning -- why two tables and not one? - 10-19-2009 , 06:13 AM



Philipp Post wrote:

Quote:
Lawpoop,

A couple folks ( myself included ) thought that there should be at least two tables -- 'donors' and 'donations' . But the poster argued that no, there would never be a holiday fund drive appeal sent out to all donors, or a year-end statement, or anything of that sort. So a single table would suffice.

From your description it seems to me that the poster would like to use
something quite simple, such as a wizard-generated bulk mailing which
for example is available in MS Word. Usually such data source is a
single table in MS Word, MS Excel or any database query on MS Access
or superior systems.

I agree that the single table solution will not scale up well,
How do you figure that?

Quote:
is not
properly normalized,
And how do you figure that?

Quote:
I would therefore vote for that beeing a misunderstanding of some kind.
If we get to vote on this, I vote that you're leaping to
entirely random conclusions.

--
Roy

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  #34  
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Philipp Post
 
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Default Re: relational reasoning -- why two tables and not one? - 10-19-2009 , 10:17 AM



Quote:
I agree that the single table solution will not scale up well,

How do you figure that?
If the requirements for this solution will be extended, you will have
to go splitting up that single table into two or more, depending on
the attributes on hand.

Quote:
is not
properly normalized,

And how do you figure that?
From what we have to guess from the description of the OP. E. g.
{donation_nbr, donator_name, donator_address, donation_amt,
donation_date}

Quote:
I would therefore vote for that beeing a misunderstanding of some kind.

If we get to vote on this, I vote that you're leaping to
entirely random conclusions.
As random as possible based on what we were told about this case.

brgds

Philipp Post

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  #35  
Old   
Cimode
 
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Default Re: relational reasoning -- why two tables and not one? - 10-19-2009 , 01:22 PM



Snipped

Quote:
I would therefore vote for that beeing a misunderstanding of some
kind.
The only misunderstanding I can see here is the one you are spreading
by attempting to establish a relationship between a logical design
effort (a process called normalization) and a vague implementation
physical performance concept related to a direct image systems's
ilmitation called scaling up (related to the increase in time of
number of physical rows stored on disk and its impact on response
time).

Since you obviously ignore the difference between the two concepts
(also called independence between the logical and physical layer of
database modeling), I doubt that anything you are posting will add
anything of value since your premice is based on utter ignorance of
database design...

Quote:
brgds

Philipp Post

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  #36  
Old   
Roy Hann
 
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Default Re: relational reasoning -- why two tables and not one? - 10-19-2009 , 01:59 PM



Philipp Post wrote:

Quote:
I agree that the single table solution will not scale up well,

How do you figure that?

If the requirements for this solution will be extended, you will have
to go splitting up that single table into two or more, depending on
the attributes on hand.
Although that is not the usual notion of what it means to "scale up"
I guessed that's probably what you had in mind. But in the absence of
any good reason to prefer one random guess at a future conceptual model
over any other, you are just firing from the hip and not improving the
design.

Quote:
is not
properly normalized,

And how do you figure that?

From what we have to guess from the description of the OP. E. g.
{donation_nbr, donator_name, donator_address, donation_amt,
donation_date}
Well, with just as much justification, my guess is that the OP's single
table is already 5NF.

--
Roy

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