You should specify the integer or unsigned format for fields when:
Packed, zoned, and binary formats should be specified for fields when:
- Using values that have implied decimal positions, such currency values
- Manipulating values having more than 19 digits
- Ensuring a specific number of digits for a field is important
Float format should be specified for fields when:
- The same variable is needed to hold very small and/or very large values
that cannot be represented in packed or zoned values.
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.