Hi!
The reason why we save the actual value with more
digits than the
precision (and why we keep the precision as an explicit value at all) is
because the value could be entered and displayed either as decimal
digits or in minutes and seconds. So internally one would save 20' as
0.333333333, but the precision is still just 2. This allows to roundtrip.
I hope that makes any sense?
Yes, for primary data storage (though roundtripping via
limited-precision doubles is not ideal, but I guess good enough for
now). But for secondary data/query interface, I am not sure 0.333333333
is that useful. What would one do with it, especially in SPARQL?
--
Stas Malyshev
smalyshev(a)wikimedia.org