Attaching an equation to a parameter

You can create an equation in the Equation form for a variety of reasons.

  • To define an equation total parameter
  • To issue an alert message to users
  • To retrieve, compare, and calculate values in the database with respect to a formula

For an equation total parameter, the equation must be associated with the parameter in the Parameter form. Other equations may not be related to a specific parameter; but they must be associated with a parameter for the equation to be triggered in a formula when users click Calc in the Formula form. For these equations, create a parameter whose only purpose is to be associated with these equations.

To attach an equation to a parameter:

  1. Open the Parameter form.
  2. Select an equation type from the list and select an existing equation.

    This table describes which equation indicator to select for your parameter.

    Equation indicator Type of parameter
    None Parameter that does not have an equation attached to it.
    Total value equation Parameter is calculated at the formula level by an equation.

    Use for non-boolean parameter types that are derived from other parameters or items. The parameter is assigned to the Equation Total category in the lab. Equation Total parameters are not displayed at the item level.

    Rollup param total test Boolean parameter (AND/OR/numeric min/numeric max) that requires an equation.

    You can assign an equation to check if a restricted item is included in the formula (parameter type OR); and issue an alert message if true. The parameter is assigned to the Rollup category.

    Calculated parameter Parameter that is calculated by an equation at the item level from other parameters, then rolled up to subsequent levels.

    The parameter is assigned to the Rollup category. Users click Calc on the Item form to calculate the parameter. In higher level formulas, the value is rolled up from the items. Do not select the Numeric Info parameter type.

    To return a string value from an equation to a parameter, select calculated parameter.

    Set the Type to a Character Info and the data type as String. Add the parameter to the lab as an informational parameter.

    The parameter is calculated as defined. After you have assigned the parameter to labs, it is shown on the Parameters tab of a formula and other Optiva objects in the assigned category.