I'd rather recommend you to change the way you use your table B (or
introduce a table C). Use two columns, the first one containing the
variable name you want to introduce and the second its value. If you want
to introduce variables of different types, just create one separate column
for each possible type.

You would need a very good reason to convince me that what you are trying
to do is sensible, and if you manage to do that you might have problems
convincing me that using Firebird is the best way to achieve it!

Set