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Back to the Data Model.
The Draft Business Rules have been defined and are listed below.
A. The Area being Modelled is :-
A Product Line.
B. The Things of Interest, ('THINGS'), include :-
B.1 Products.
B.2 Product Categories.
B.3 Product Characteristics.
C. These THINGS are Related as follows :-
C.1 A PRODUCT can be in one and only one PRODUCT_CATEGORY.
C.2 A PRODUCT can have zero, one or many PRODUCT_CHARACTERISTICS.
D. Other Characteristics of these THINGS include :-
D.1 A PRODUCT can have zero or one TYPICAL_BUYING_PRICE.
D.1 A PRODUCT can have zero or one TYPICAL_SELLING_PRICE.
E. Sample Data includes :-
To be determined
F. Typical Enquiries include :-
F.1 What is the typical selling price for 100 Cinnamon Sticks?
G. DESIGN NOTES :
G.1 Handling Sub-Categories
A general approach is to link the Product Table to itself. This allows flexible structures within the Products.
A fixed approach is to have separate Tables for Categories and Sub-Categories.
In this case, the general approach is recommended because change is likely to occur in the future.
G.2 Prices are defined as characters instead of money, in order to store things like '$5 for 100 Sticks'
Barry Williams
Principal Consultant
Database Answers
8th. February 2003
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