Please critique my ERD. - Page 2

holsen32 · #16 (**permalink**) 08-04-10, 05:54

Quote:

Originally Posted by r937

i completely agree with your point, that a true 1-to-1 relationship is impossible because you cannot enter values on both sides simultaneously (and therefore it has to be a 1-to-0-or-1 relationship)

i would just like to mention that this is called "catch 22" not "cats 22" -- it is named after an idea in a book with that actual title, "catch 22"

that's very funny. I am aware of the book. I'm hoping that the editor "auto-corrected" my text.

mike_bike_kite · #17 (**permalink**) 08-04-10, 08:14

Quote:

Originally Posted by Magian

I am requesting critiques of a ERD that I have created

Random points:
As mentioned above there are no primary keys or foreign keys - these are essential.

for us to understand your design.

All the 1:1 relationships between the tables are almost certainly wrong ie

Surely a customer could have many invoices but your schema indicates just one?

Location and Insurance tables hold people in the Contact table - could you move the drivers in here as well?

Can a driver really only drive one truck?

Should the Insurance fields be inside the truck (or driver) tables?

What's a FOB??

Pat Phelan · #18 (**permalink**) 08-04-10, 09:43

A fob is a thingie that holds your keys. FOB is an acronym for "Freight On Board" which to the driver means the location where freight is loaded and to the shipping clerk means that shipment is pre-paid. The same term is used in two potentially different ways.

-PatP

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