[AccessD] Access and SQL Server

Lambert,

<<No you cannot just go in and change it at will. You also have to go find
all the records in all the tables that use that Autonumber value as the
foreign key back to the table they are relate to.>>

  Sorry if that wasn't obvious, but yes certainly you would.  However I
could do that at any time.

  Once it's turned into an attribute though, it takes on meaning.  You still
could at that point change it, but not without changing something else.
It's no longer a matter of simply updating the data.

  For example, an asset tag number, which has been applied to all assets.
New admin comes in and now wants all the numbers to be 4 digits instead of
the current 8.

  I can't simply go into the data and decrease the digits without going to
every asset and re-labeling it.

Jim.

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Heenan, Lambert
Sent: Thursday, March 03, 2011 11:59 AM
To: Access Developers discussion and problem solving
Subject: Re: [AccessD] Access and SQL Server

"  However it can be made into a surrogate PK by assigning it to the object
it's associated with, or in other words, making it an attribute.
"Surrogate" means "to take the place of" and an auto number when it's just
applied to a table cannot do that because it has no meaning.  It's a pointer
or tag in a physical context and that's it.  Yes it is unique, but I can go
in and change it at will."

No you cannot just go in and change it at will. You also have to go find all
the records in all the tables that use that Autonumber value as the foreign
key back to the table they are relate to. So that's why I don't make an
Autonumber PK any kind of meaningful attribute for a record.

Real data used to construct Natural PKs can change too, and then it gets
messy.

Lambert's 2 cents.
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