> If I use a COMPUTED column, any time I use SELECT * FROM
> OPS_STOP_REC that column is going to be evaluated. This would end up
> doing a lot of I/O in those cases where I don't care about the value
> of the computed column.

I'd bet that if you can afford to be careless about specifying the
column list exactly, and thereby causing already a lot of overhead in
the datastream and buffers, the tiny little bit of computing the
column should not matter.

But that's just an uneducated guess, since I am not in too deep in
Firebird technics.

As an alternative, you can put the functionality you want into one
stored procedure (using, for example, a For... Select... into...).
You can make extra use of some "execute statement" here and there to
generalize the procedure and call the same procedure for different
purposes.

Extra overhead as well, but only due when actually querying the data.

best regards,
André