Say I have field Ice\_Cream.flavor, with the current choices in lookup table Flavor.flavor. 

I use Flavor.flavor like an enum() list, storing the **value**, **not** the record ID, in Ice\_Cream.flavor. If Flavor.flavor changes, I don't want to update Ice\_Cream:flavor. I want it to stay as created.

Should I set up Ice\_Cream.Flavor as a foreign key, so I can see the source of the values in my ER diagram, or not?