formula

Formula

Description

Examples

Related Links

Description

You can create fields that are calculated instead of being entered by the user. These fields are called the formula fields. When you create a formula field, you have to specify the formula expression based on which the value for this field is calculated. Depending on the output of the formula, the value held by a formula field could be numeric values, text values, dates, and durations. The formula evaluation is nothing but expression evaluation and is explained in detail in Expressions.

Example: In the below given sample, the field TotalMarks is of type formula, English and Maths are the fields in the form.

TotalMarks ( type = formula value = English + Arts )

But one formula field cannot be used in another formula field i.e. The following code is invalid, because the formula field TotalMarks is used in another formula field AverageMarks.

TotalMarks
(
    type = formula
    value = English + Arts
)
AverageMarks
(
    type = formula
    value = TotalMarks / 2
)

Note:

Since formula fields are calculated, they do not get displayed in the form when it is rendered. User can choose to view these fields in the form view.

Complete Sample

application "Student marks database"
{
    page "Enter marks"
    {
        form  Students_Mark_Sheet
        {
            displayname = "Students Mark Sheet"
            Student_Name
            (
                displayname = "Student Name"
                type = text
            )
            English
            (
                type =  number
                decimalplace =  2
            )
            Arts
            (
                type = number
                decimalplace =  2
            )
            TotalMarks
            (
                type = formula
                value = English + Arts
            )
            AverageMarks
            (
                type = formula
                value = (English + Arts) / 2
            ) 
        }
        list "View student marks"
        {
            Students_Mark_Sheet
        }
    }
}

Note:

All types of form fields except multiple select fields can be used in formulas.

The operators/functions that can be used in formulas can be found in the sections Operators and Built-in functions.

The formulas will get recalculated when,

the formula is modified

the values of the fields participating in the formula gets modified (when a record is updated).