It depends on the values, rather than on the scale and precision of the column
(although, of course, that does limit the possible values). Zero takes just 1
byte. For positive numbers 1 more byte is needed for every pair of digits from
the least significant non-zero pair of digits to the most significant. For
example, 8749000 would take 4 bytes - one for the sign and exponent, and three
for the digit pairs 08, 74 and 90.  Negative numbers normally take one more byte
than the corresponding positive number.


-----Original Message-----
Sent: Friday, 25 August 2000 1:32


When trying to estimate the size of an index we want to create, how many bytes
do we allow for a NUMBER column?  How many bytes does Oracle store for each
digit of a NUMBER data type.  The documentation does not explicitly state this.

For example, what would be the number of bytes for the following column
definitions:

1.  NUMBER (4)
2.  NUMBER (10,5)
3.  NUMBER (13,4)
4.  NUMBER