15. VIFRED Field Specifications : Derived Fields
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Derived Fields
A derived field is a field whose value is based on the value of another field, called the source field, or constants. For example, your form could contain the following fields:
Price (price of an item)
Quantity Sold (total number of items sold)
Total Amount Sold (value in the Price field multiplied by the value in the Quantity Sold field)
The Total Amount Sold field is a derived field, and the Price and Quantity Sold fields are its source fields.
Both simple fields and table field columns can be derived fields. VIFRED calculates the value of a derived field from a derivation formula, which you specify.
The derived field must be nullable when:
One of its source fields is nullable
The derivation formula contains an aggregate
Derived fields cannot have the following attributes:
Default values
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