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000006_rts _Mon Aug 16 15:21:15 1993.msg
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Received: from boojum.CS.Arizona.EDU by optima.CS.Arizona.EDU (5.65c/15) via SMTP
id AA12862; Mon, 16 Aug 1993 15:21:16 MST
Date: Mon, 16 Aug 1993 15:21:15 MST
From: "Rick Snodgrass" <rts>
Message-Id: <199308162221.AA02904@boojum.cs.arizona.edu>
Received: by boojum.cs.arizona.edu; Mon, 16 Aug 1993 15:21:15 MST
To: tdbglossary@cs.arizona.edu
Subject: Re: Status and Proposals
I think that Christian and the editorial board are doing a fantastic job
in finalizing the glossary.
I have but a few comments on the proposals that Christian sent out for
comments.
"Transaction commit time is lengthy ($-$E2), but more importantly, the
name appears to indicate that the transaction time associated with a
fact must be identical to the time when that fact is committed to the
database, which is an unnecessary restriction and is imprecise ($-$E8,
$-$E9). It is imprecise because the transaction time of a fact in
general is a transaction-time element, not a single time instant as
implied."
I suggest removing "and is imprecise." and instead talk about the imprecision
only in the last sentence: "It is also imprecise ($-$"...
Proposal 3:
Entry: transaction-timeslice operator
New entry: Replace the sentence (in the definition) "It also takes as
argument a time value not exceeding the current time, {\em NOW\/}." by
"It also takes as an argument a time value---a chronon in discrete
models and a time instant in continuous models---not exceeding the
current time, {\em NOW\/}."
It seems that it would be just as clear, and less wordy, to use the following
prose.
"It also takes as an argument a time instant that does not exceed the
current time, {\em NOW\/}."
"A span is {\em fixed\/} if it possesses the special property that
it's duration is independent of the context."
Replace "it's" with "its".
are fixed, consider ``one month,'' an example of a variable span. The
duration of this span may be any of 28, 29, 30, and 31 days, depending
on the context."
Perhaps add "(in the Gregorian calendar)" somewhere in this sentence.
"Any span is either a fixed span or a variable span. The obvious
Replace "The" with "An".