MV Data Types
Data type for the MultiValue internal representation of dates. It represents the elapsed number of days since December 31, 1967. This data type extends Caché %Date, which represents the elapsed number of days since December 31, 1840. For further details, refer to the MVBasic DATE function and %MV.Date class in the InterSystems Class Reference.
Data type for the MultiValue internal representation of numeric values. This data type corresponds to %Numeric, but has an additional DESCALE parameter.
DESCALE only exists as a parameter for %MV.Numeric, and controls descaling — moving the decimal point for numbers stored with implicit decimals. If you expect numbers to be entered accurately with decimals, then you need to descale on input to move the decimal to the internal format (in most cases, remove the decimal).
SCALE is inherited from %Numeric, and controls the number of decimal places that the number is rounded to, usually reducing precision. There's no sense in scaling on input because you can't add precision that isn't there. DESCALE is reversable, because it just moves the decimal. SCALE is not reversible, because it reduces the precision.
A null value is stored in %MV.Numeric as NULL. Descaling is ignored for null values.
For further details, refer to the %MV.Numeric class in the InterSystems Class Reference.
Caché SQL Data Types