What are the largest and smallest NUMBER values?

From: Jonathan Gennick <jonathan_at_gennick.com>
Date: Sun, 3 Apr 2005 21:47:56 -0400
Message-ID: <71646125168.20050403214756@gennick.com>

I'm trying to nail down the range of NUMBER values. The range I come up with, based on a maximum precision of 38 and a scale range of -84 through 127, is illustrated by the following code block:

DECLARE
   min_num NUMBER(38,127);
   max_num NUMBER(38,-84);
BEGIN
   /* 127 is largest scale, so begin with 1 and move

      decimal point 127 places to the left. Easy. */    min_num := 1E-127;
   DBMS_OUTPUT.PUT_LINE(min_num);

   /* -84 is smallest scale value. Add 37 to normalize

      the scientific-notation, and we get E+121. */

   max_num := 9.9999999999999999999999999999999999999E+121;

   DBMS_OUTPUT.PUT_LINE(max_num);
END;
/

The results I get are:

1.000000000000000000000000000000000000000000000000000000000000000000000000000000

000000000000000E-127

9.999999999999999999999999999999999999900000000000000000000000000000000000000000

000000000000000E+121

These results make sense to me. What troubles me is that the SQL Reference gives 1.0E-130 as the low end (versus my 1.0E-127). The SQL reference also gives "up to, but not including 1.0E126" as the high end. It would seem that the manual is incorrect. On the other hand, perhaps there is some subtle point that I am just not seeing. So I'm throwing my question, and my code out to see whether anyone can spot a flaw in my thinking here.

Best regards,

Jonathan Gennick --- Brighten the corner where you are http://Gennick.com * 906.387.1698 * mailto:jonathan@gennick.com

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Received on Sun Apr 03 2005 - 21:51:44 CDT