Physical Storage Of NUMBER Data Type

How does Oracle physically store columns of data type NUMBER? I know that the maximum physical size of this data type is 22 bytes. I know that the maximum number of significant digits for this data type is 38.

I assume that a valid calculation to get from 38 to 22 is:   

   (# significant digits/2) + 3 overhead bytes   

However, the USER_IND_COLUMNS and USER_TAB_COLUMNS show the column length for a NUMBER column always as 22.   

Is the previous calculation correct for determining the physical storage requirements for a NUMBER data type? If not, what is? If so, what is the reason for the two user views displaying the length as always being 22?   

Thanks,   

Alan N. Turner
Sr. Strategy DBA
Systems and Equipment Sector
Texas Instruments, Inc.
Internet: anturner_at_sc1500.dseg.ti.com Received on Fri Mar 18 1994 - 18:18:12 CET