[AccessD] normalization question

Well, I did think of that -- but then how do you determine which Mary Smith
did what in your database? Through relationships of course, but one false
move and zip...... you're telling Mary Smith at 101 First Street that she is
indeed pregnant... No, you're not pregnant, Mary Smith... Well, yes you are
-- when actually Mary Smith at 101 First Street IS pregnant, it's Mary Smith
at 201 Main Street that is NOT pregnant --  know what I mean? The potential
for mistakes seems horrendously large. One wrong relationship (pun intended)
and let the data fall where it may! :) Of course, that would be true in any
database -- but we tend to think of relating the data and transactions to
the person or business, not the address or the hire date, or birth date, or
whatever other value we end up having to use -- because Mary Smith isn't a
duplicate, just her name is. :) 

Let's do it this way -- you have a table with just one Mary Smith, but you
have two addresses linked to Mary Smith. Does Mary Smith have two addresses,
or are there two Mary Smith's? You can't possibly know and the difference
might be important. ON the other hand, you can easily see if NameID: 101
Mary Smith has two addresses or if NameID: 101 Mary Smith has one and
NameID: 306 Mary Smith has another. What if it's <gasp> both? What if one
Mary Smith has two addresses and one Mary Smith has none or one? Or, what if
there are 3 Mary Smiths... Could I BE more obnoxious? :)  

In the end, it seems like there has to be another distinguishing value, as
Martin suggests or we have to accept some redundancy. 

OK, let chaos ensue! ;) 

Susan H. 

By having a table of people, of course.  There is a one-to-many relationship
between people and names.  (Or more accurately a many-to-many relationship -
but let's not get into that!)  Each person with the name "John Smith" would
be represented by a record (in the people table) containing a pointer to
that name in the name table.

If you had a table of eye colors, how would you deal with real people with
the same eye color?  It's the same question as yours, really.  Eye color
doesn't identify a person uniquely: nor does a name (well, some might).

Sorry to sound simplistic, but that's it, really.  No cliff to step off.
There remains of course the issue of how to identify people uniquely - but
that, as they say, is another story ...

John


> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Susan 
> Harkins
> Sent: 16 May 2004 21:43
> To: 'Access Developers discussion and problem solving'
> Subject: [AccessD] normalization question
> 
> 
> If a table contains only names -- say first and last -- and you relate 
> those records to other tables -- how to you deal with real people with 
> the same name? I feel like I'm stepping off a cliff here...
>  
> Susan H. 
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