Non-standard number data types in Oracle I'm not sure that this question belongs to this StackExchange.
I've asked this question on StackOverflow:

Besides the &quot;usual&quot; number data type where precision is greater then scale there are many &quot;non-standard&quot; number data types where scale greater then precision or where scale is negative.
For example
NUMBER(2, 5) means that there are 5 digits in the fractional part, 3
of them is obligatory zeros. NUMBER(2,-6) Here the scale is -6, which
means the value is rounded to millions and the precision is 2, so 2
significant digits can be stored. Can somebody provide examples of
using such data types in practice?

Some clarifications:
I am very interested in the motivation for using such data types (NUMBER(2, 5) and NUMBER(2,-6)).
What tasks can such a table design solve?
It prevent Aoplicatuions from inserting invalid data. P.For example for many currecncies it maks no senes to have more than 2 digits right from the decimal point.