Oracle DB: NUMBER data type

The following examples illustrate the functionality of NUMBER data type precision and scale:

Input Data	Specified As	Stored As
7,456,123.89	`NUMBER`	7456123.89
7,456,123.89	`NUMBER(*,1)`	7456123.9
7,456,123.89	`NUMBER(9)`	7456124
7,456,123.89	`NUMBER(9,2)`	7456123.89
7,456,123.89	`NUMBER(9,1)`	7456123.9
7,456,123.89	`NUMBER(6)`	(not accepted, exceeds precision)
7,456,123.89	`NUMBER(7,-2)`	7456100

If precision and scale are not defined then any number, which observes the following size can be stored:

Positive numbers in the range 1 x 10^-130 to 9.99…9 x 10¹²⁵ with up to 38 significant digits
Negative numbers from -1 x 10^-130 to 9.99…99 x 10¹²⁵ with up to 38 significant digits
Zero
Positive and negative infinity (generated only by importing from an Oracle Database, Version 5)

(source: http://docs.oracle.com/cd/B28359_01/server.111/b28318/datatype.htm#CNCPT313)