Re: ID field as logical address

From: David BL <>
Date: Tue, 2 Jun 2009 19:56:42 -0700 (PDT)
Message-ID: <>

On May 29, 8:54 pm, "Walter Mitty" <> wrote:

> Now, if we update the LastName, the FirstName, and the Phone number of an
> entry, it's still the same entry, because the ID field retains the same
> value.

That's rather fuzzy until you say what you mean by 'entry'. Does it mean value or variable? It cannot be referring to the tuple because after the update it is a different tuple. Evidently 'entry' means 'variable' in the above. Substitute and you will see it makes sense.

> So, Brian's claim that deleting a value and inserting a new one is somehow
> really different from updating an existing value works in this model, if
> you regard ID as somehow "special", and not "part of the value recorded in
> the table".

For a given variable that holds a set of values you can indeed delete a value or insert a value but you cannot update a value. You can only update a variable. Received on Wed Jun 03 2009 - 04:56:42 CEST

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