ORACLE NUMBER类型详解

1>.NUMBER类型细讲：Oracle number datatype 语法：NUMBER[(precision [, scale])]简称：precision --> p scale;;--> s

NUMBER(p, s)范围： 1 <= p <=38, -84 <= s <= 127保存数据范围：-1.0e-130 <= number value < 1.0e+126保存在机器内部的范围： 1 ~ 22 bytes

有效为：从左边第一个不为0的数算起的位数。s的情况：s > 0 精确到小数点右边s位，并四舍五入。然后检验有效位是否 <= p。s < 0 精确到小数点左边s位，并四舍五入。然后检验有效位是否 <= p + |s|。s = 0 此时NUMBER表示整数。

eg:Actual DataSpecified As Stored As----------------------------------------123.89NUMBER 123.89123.89NUMBER(3);;124123.89NUMBER(6,2)123.89123.89NUMBER(6,1)123.9123.89NUMBER(4,2)exceeds precision (有效位为5, 5 > 4)123.89NUMBER(6,-2) 100.01234NUMBER(4,5).01234 (有效位为4).00012NUMBER(4,5).00012.000127;;;;NUMBER(4,5).00013.0000012;;;NUMBER(2,7).0000012.00000123;;NUMBER(2,7).00000121.2e-4NUMBER(2,5)0.000121.2e-5NUMBER(2,5)0.00001123.2564;;;NUMBER;;;;;123.25641234.9876;;NUMBER(6,2)1234.9912345.12345NUMBER(6,2)Error (有效位为5+2 > 6)1234.9876;;NUMBER(6);;1235 (s没有表示s=0)12345.345;;NUMBER(5,-2) 123001234567;;;;NUMBER(5,-2) 123460012345678;;;NUMBER(5,-2) Error (有效位为8 > 7)123456789;;NUMBER(5,-4) 1234600001234567890;NUMBER(5,-4) Error (有效位为10 > 9)12345.58;;;NUMBER(*, 1) 12345.60.1NUMBER(4,5)Error (0.10000, 有效位为5 > 4)0.01234567;NUMBER(4,5)0.012350.09999;;;;NUMBER(4,5)0.09999