Subject Re: Decimal field precision question
Author jeff_j_dunlap
> I think the type you wish is Decimal(6,3) theorically 999.999.
> (3,3) would be something like 0.999.
> *But* FB does not impose the limit by itself, you need to use a CHECK
> CONSTRAINT to limit the maximum filed value, the type used by FB to
> store decimal(6,3) is a 32 bit integer and the maximum allowed values
> will be 2^31/1000

Thanks for the response. I read the IB6 docs a little more and did a
litte more testing.

In my limited experience, it appears that NUMERICS (with scale) and
DECIMALS (with scale) store the date exactly the same way, except when
dealing with smaller figures such as NUMERIC( and below. The
reason is that according to the IB6 docs, a NUMERIC( is stored as
a smallint and a DECIMAL( is stored as an integer. This
basically means that if you only need to store figures in the
range, using a NUMERIC( vs a DECIMAL( will save you 2 bytes
for each field since an integer occupies 4 bytes and a smallint
occupies 2 bytes.

I'm going to stick with Decimal(6,3) for storing interest rates ranging
from p.sss to ppp.sss

I'm learning FB using dialect 3 and as far as that goes, I can't see a
difference between choosing NUMERIC(precision.scale) or DECIMAL
(precision.scale). With this said, I think that I'm going to
standardize on using NUMERIC instead of DECIMAL so that if I ever need
to store smaller numerics (, I will save myself 2 bytes per field.

Best Regards,