Overview FlowFields are the fields which are used only to display the result of a calculation based on the “calcFormula” property. They are not the physical fields, as they do not store any value in the database. Interestingly, the values in the flowFields exists only at runtime. By default, the flowfields are initialized to 0.  There are seven (7) types of flowFields, namely, sum, average, exist, count, min, max and lookup. We define a flowField by defining the fieldClass property as FlowField and giving the calcFormula property as per our requirement. Below, we have defined a flowField, “Name”, which is used to display the name of the customer. Here we have created the flowField of type “lookup”.When the FlowField is the direct source of expression of a control on page, then  FlowField is updated automatically based on calcFormula property when the page is displayed. Now, if a flowfield is initialized to 0, how do we update the value of that flowfield? The answer to this question is using CalcFields Method. Let us learn about the calcFields method.