I want to create a "materials" price list but the material prices need to support possibly more then one unit of measure. Eg... Rebar can cost $/Unit Length but the price of rebar maybe required in Unit Length (eg. feet) or Unit Mass (eg. lbs).

Only a few materials would require more then one conversion for the price so how should I setup the table structure?

Code:
MATERIAL_CATEGORY
ID | Descr
----------
1   | Rebar

MATERIAL
ID | Descr | fkCategoryID
------------------------
1  | 10M   | 1 

MATERIAL_PRICE_BOOK
fkMaterialID | Price | fkUnits | fkCurrencyUnits
---------------------------------------------
1               | 1.29  | ft        | CAN

UNIT
Unit | Desc     | fkUnitCategory
---------------------------
ft    | Foot     | 1
lbs   | Pounds | 2

UNIT_CATEGORY
CategoryID | Descr
-------------------
1               | Length
2               | Mass
In the above table structure you can see that for 1 ft of 10M Rebar it will cost $1.29 CAN.

Now how can I set this up if I want to get the cost for 1 pound of rebar.

Mike B