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Home -> Community -> Usenet -> comp.databases.theory -> Re: A good book
"Chris Smith" <cdsmith_at_twu.net> wrote in message
news:MPG.1f17250df9bb8890989752_at_news.altopia.net...
> Hi,
>
> Let's say you met someone who has a strong mathematical background, a
> long history of development of mainly business application software, a
> perfectly fine understanding of writing SQL queries in practical
> settings. This person understands that OO languages are somewhat
> arbitrary, but not particularly convinced that they are evil.
> Similarly, he is not convinced of the need for writing significant
> amounts of code in declarative style, nor that the existence of a simple
> formal mathematical model behind relational databases is necessarily
> exploitable to produce better software. Let's further say that you
> could get said person to read one book. What would it be?
>
> (Yes, this is somewhat autobiographical...)
Is /this/ the sort of connection between logic and the RM that you're looking for?
"Databases are /structured/ collections of facts or, more precisely, represent propositions--assertions of facts purported to be true. Consider a hotel reservations database, which records propositions of the following general form
Reservation identified by reservation number (RES#), made for room with number (ROOM), has scheduled arrival date (ARR_DATE) has scheduled departure date (DPT_DATE)
Formally, this generalized form of proposition is a *predicate*, and the terms in parentheses are *value placeholders*. Substituting specific values for the placeholders yields propositions about specific reservations. For example, the values
(990000, 333, 7/26/1995, 7/28/1995)
yield the proposition
Reservation identified by reservation number 990000 made for room with number 333 has scheduled arrival date 7/26/1995 has scheduled departure date 7/28/1995
Propositions in the database are represented by rows in tables--sets of values--which, when substituted for the placeholders in the predicate, yield those propositions..."
"Practical Issues in Database Management", by Fabian Pascal, pp 46..47. Received on Sat Jul 08 2006 - 00:04:57 CDT
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