>>>> In other words, so that a new record is created in the keys table if a call is made with the name of a table that is not yet in the table.
>>
>>Why would you want this? If you or another develop supply the wrong tablename, maybe spelled incorrectly, you would get another row and might not realize the problem that has been introduced.
>
>Yes, misspelling is a problem. On the other hand, it would simplify updating a client site as product evolves and new tables are added.

True, but you could do the same thing explicitly with a script when the application was deployed.

To answer your original question, if the variable's value was NULL, the requested table probably didn't exist and you could insert the row at that point.

But I still don't think it's a good idea.

-Mike