Guidelines for Choosing the Numeric Format for a Field

You should specify the integer or unsigned format for fields when:
Packed, zoned, and binary formats should be specified for fields when:
Float format should be specified for fields when:

However, float format should not be used when more than 16 digits of precision are needed.

Note: Overflow is more likely to occur with arithmetic operations performed using the integer or unsigned format, especially when integer arithmetic occurs in free-form expressions. This is because the intermediate results are kept in integer or unsigned format rather than a temporary decimal field of sufficient size.