value calculation

[kyle]

Here's a simplified version of my problem:

Material Table:
-Species of Wood
-Cost of Species of Wood



Product Table:
-Type of Product
-Amount of Wood Needed
-Labor Cost of Product

Order Table:
- (lookup) Type of Product
- (lookup) Species of Wood
- (lookup) Labor Cost of Product
- (lookup) Cost of Species of Wood * (lookup) Amount of Wood Needed
- labor cost + cost of wood needed


I'm having problems with the last table. The function where I'm looking up 2 values and multiplying them together is causing some problems. For inventory purposes I would like to make sure that the material is being used and not lost.

Does anyone have a sugestion.

I can provide the files if more information is needed.

[RuralGuy]

You are not using Lookup Fields are you? http://www.mvps.org/access/lookupfields.htm

[kyle]

I am curently using lookup fields, however I am open to any sugestions.

[RuralGuy]

My suggestion is "don't use them". ComboBoxes on forms that look up values is fine, but not at the table level. All they do is nonfuse the programmer.