ORACLE Number Type detailed

1>. Number type fine-talk:
Oracle number datatype syntax: number[(precision [, scale])]
Abbreviation: Precision--> P
Scale--> S

Number (P, s)
Range: 1 <= P <=38, -84 <= s <= 127
Save data range: -1.0e-130 <= number Value < 1.0e+126
Stored within the machine range: 1 ~ bytes

Valid: The number of digits from the first number on the left that is not 0.
The case of S:
s > 0
Accurate to the right of the decimal point s bit, and rounded. Then verify that the valid bit is <= p.
S < 0
Accurate to the left of the decimal point, and rounded. Then verify that the valid bit is <= p + S.
s = 0
Number represents an integer at this time.

eg
Actual Data Specified as Stored as
----------------------------------------
123.89 number 123.89
123.89 Number (3) 124
123.89 number (6,2) 123.89
123.89 number (6,1) 123.9
123.89 number (4,2) exceeds precision (valid bit 5, 5 > 4)
123.89 number (6,-2) 100
.01234 number (4,5). 01234 (Valid bit 4)
.00012 number (4,5). 00012
.000127 number (4,5). 00013
.0000012 number (2,7). 0000012
.00000123 number (2,7). 0000012
1.2e-4 # (2,5) 0.00012
1.2e-5 # (2,5) 0.00001
123.2564 number 123.2564
1234.9876 number (6,2) 1234.99
12345.12345 number (6,2) Error (valid bit for 5+2 > 6)
1234.9876 Number (6) 1235 (s does not indicate s=0)
12345.345 number (5,-2) 12300
1234567 number (5,-2) 1234600
12345678 number (5,-2) Error (valid bit 8 > 7)
123456789 number (5,-4) 123460000
1234567890 number (5,-4) Error (Effective bit > 9)
12345.58 Number (*, 1) # 12345.6
0.1 number (4,5) Error (0.10000, valid bit 5 > 4)
0.01234567 number (4,5) 0.01235
0.09999 number (4,5) 0.09999