Steve Jones - Editor (8/18/2010)
It could be N/A, but that implies a specific meaning. Using NULL there as a placeholder works, but you are assigning a value to NULL. I prefer to keep it as "unknown" as in there will be a ship date, but right now it's unknown.
Good point - if we use NULL for miles per gallon for an electric car, it doesn't really mean "unknown" in that case, but "N/A" since the MPG doesn't even apply in this case. We're already seeing inconsistencies here. So what would all of you say to do in this case? Use a NULL anyway since it "works?" I would probably use the NULL there if it was a numeric field and couldn't change the field's type easily. But aren't we already bending the rules of NULLs? We can redefine a NULL on a whim?
The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge. - Stephen Hawking