Re: Database design, Keys and some other things
Date: 24 Sep 2005 10:58:18 -0700
Message-ID: <1127584698.565076.211910_at_z14g2000cwz.googlegroups.com>
The tables are simplified for the purpose paying attention to keys.
There is the complete explanation of this example, definition of Key
and others things related to it, on my website www.dbdesign10.com.
CarKey is Key and in my opinion it has more appropriate definition of
Key. Current definition of Key in the database theory and its
implementation has limitations, especially for the complex database
projects.
I would like to emphasizes the relation between CarKey and CarID ( I
call this E-relation in my Data Model because this is the entity
level).
For the table Car following set of the pairs
(23, vin1), (24, vin1) and (25, vin1)
identify one car in the Real World. (much better then the pair (23,
vin1))
And for these values it is "True" that they are in the relation.
Vladimir Odrljin Received on Sat Sep 24 2005 - 19:58:18 CEST