Original: http://www.jb51.net/article/37633.htm
Number (precision, scale)
A) precision represents a valid bit in the number, and if no precision is specified, Oracle uses 38 as the precision.
b) If scale is greater than 0, indicates the number of digits to the right of the decimal point, the default setting of scale is 0, and if scale is less than 0, Oracle will trade the number to the specified number of digits to the left of the decimal point.
c) The value range for precision is "1---38" and the value range for scale is " -84---127".
d) The number integer part allows the length to be (Precision-scale), regardless of whether the scale is positive or negative.
e) If precision is smaller than scale, it means that there are no integers stored in decimals.
f) Precision indicates the number of significant digits,
valid digits: The decimal point and the minus sign do not count toward the number of significant digits from the first number on the left that is not 0Scale indicates the exact number of bits, which means
The exact number of digits to the left or right of the decimal point (+-).
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Example of number value type:
Actual value |
Data type |
Store value |
1234567.89 |
Number |
1234567.89 |
1234567.89 |
Number (8) |
1234567 |
1234567.89 |
Number (6) |
Error |
1234567.89 |
Number (9,1) |
1234567.9 |
1234567.89 |
Number (9,3) |
Error |
1234567.89 |
Number (7,2) |
Error |
1234567.89 |
Number (5,-2) |
1234600 |
1234511.89 |
Number (5,-2) |
1234500 |
1234567.89 |
Number (5,-4) |
1230000 |
1234567.89 |
Number (*,1) |
1234567.9 |
0.012 |
Number (2,3) |
0.012 |
0.23 |
Number (2,3) |
Error |
h) For precision, scale can also be expressed as follows
The precision of the fixed-point number (p) and scale (s) follows the following rules:
1) Oracle will error when the length of the integer part of a number > P-s
2) When the length of a number of decimal parts > S, Oracle rounds.
3) when S (scale) is negative, Oracle rounds the s number to the left of the decimal point.
4) When s > P, p indicates the number of digits to the left of the S bit after the decimal point, and if the Oracle error is greater than P, the number of s bits to the right after the decimal point is rounded
Subclass of Number Type
A) Oracle does not already have an int type, and in order to be compatible with another database, the int type is added as a subset of the number type.
b) The int type can store only integers, number can store floating-point numbers, or integers can be stored.
c) When the Oracle database is built, Decimal,numeric does not have precision, and Oracle automatically handles it as an integer, with precision, and Oracle automatically processes it to number.
d) Oracle can represent any complex digital data using only number (M,N).
e) decimal,numeric,int such as SQL, DB2 and other database data types, Oracle for compatibility before the introduction of it, but in fact inside Oracle or in the form of a number to deposit.
"Go" Oracle Database Number data type
