Hello! Generally speaking, regarding performance, is expensive having
calculated fields?
Not complex ones, I mean this type of thing:
... COMPUTED BY (cast(qty * price * tax / 100 as money 2))
So far I don't notice any difference but I'd like to hear opinions about
whether is a good
idea using them.
Probably having a real field, maintained with a trigger is better? I don't
like having redundant
data in my database, but I'm note sure what is the better option: waste a bit
of space or
(probably) decrease performance??
?
I've heard (don't remember who said it, and since I don't use calculated fields
much myself, I cannot tell how reliable this information is) that calculated
fields ought only to refer to the current record, i.e. not a different table or
different record in the same table. So, as long as qty, price and tax all are
part of the same record as your COMPUTED BY value, this ought to be fine. If
they are stored in different lookup tables, then a view or a trigger maintained
field may be preferrable.
Hopefully, others will verify this or tell that I'm wrong.
Set