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
• Mandatory
• Force upper or lower case
• Display only
• Scrollable