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Creating FlowFields and FlowFilters

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This article describes the procedure and the properties used to create FlowFields and FlowFilters.

A FlowField performs a set of calculations and displays the results immediately. A FlowFilter displays the results based on the user input to calculate the filtered values that affect the calculation of a FlowField. The FlowFields and FlowFilters aren't physical fields; these fields act as a virtual field, which doesn't actually exist in the database. They're a description of a calculation and a location for the result to be displayed which is typically derived in the CalcFormula Property.

For more information about the FlowField type, see FlowFields overview, and for more information about the FlowFilter type, see FlowFilter Overview.

Classifying the field type

In order to create FlowFields and FlowFilters, you must first classify the field type by using the FieldClass Property. For more information, see FieldClass Property. By classifying the field as a FlowField or a FlowFilter type, you enable the fields to act as a virtual field whose value can be dynamically derived based on the calculation formula.

Calculation formula

A FlowField type is always associated with a calculation formula that determines how the FlowField is calculated. Likewise, the FlowFilter type is associated with the calculation formula. To perform the calculations by using the FlowField and FlowFilter type, you must derive those fields in the calculation formula, which you classify in the table. You can choose from several methods of calculations including sum (total), average, maximum value, minimum value, record count, lookup, and more, by using the CalcFormula Property. For more information about the syntax and formulas, see CalcFormula property.

Example

In the following example, MyTable sets the Global Dimension 1 Filter and Global Dimension 2 Filter fields whose values are based only on the dimension values included in the filter. Also, some of the following fields formulate the currency filter to one single currency because you don't store the filter value on the entries, hence you define the Currency Filter as a FlowFilter type. Total Amount, Amount upper bound, Amount lower bound, First Entry, and Customer Balance are classified as a FlowField type and here you specify the calculations. These fields display the results immediately based on the filters that you apply in the user interface.

table 50123 MyTable
{
    fields
    {
        field(1;MyField; Decimal)
        {
            Description = 'New field';
        }

        field(2;"No."; Code[20])
        {
            Description = 'Serial number of the service';
        }

        field(3;"Global Dimension 1 Filter"; Code[20])
        {
            FieldClass = FlowFilter;
        }

        field(4;"Global Dimension 2 Filter"; Code[20])
        {
            FieldClass = FlowFilter;
        }

        field(5;"Currency Filter"; Code[10])
        {
            FieldClass = FlowFilter;
        }

        field(6; "Total Amount"; Decimal)
        {
            FieldClass = FlowField;
            CalcFormula = Sum("Detailed Cust. Ledg. Entry"."Amount (LCY)"
            where ("Customer No."=Field("No."),
            "Initial Entry Global Dim. 1"=Field("Global Dimension 1 Filter"),
            "Initial Entry Global Dim. 2"=Field("Global Dimension 2 Filter"),
            "Currency Code"=Field("Currency Filter")
            ) );
        }

        field(7; "Amount upper bound"; Decimal)
        {
            FieldClass = FlowField;
            CalcFormula = max ("Detailed Cust. Ledg. Entry"."Amount (LCY)"
            where ("Customer No." = Field ("No."),
            "Initial Entry Global Dim. 1" = Field ("Global Dimension 1 Filter"),
            "Initial Entry Global Dim. 2" = Field ("Global Dimension 2 Filter"),
            "Currency Code" = Field ("Currency Filter")
            ));
        }

        field(8; "Amount lower bound"; Decimal)
        {
            FieldClass = FlowField;
            CalcFormula = min ("Detailed Cust. Ledg. Entry"."Amount (LCY)"
            where ("Customer No." = Field ("No."),
            "Initial Entry Global Dim. 1" = Field ("Global Dimension 1 Filter"),
            "Initial Entry Global Dim. 2" = Field ("Global Dimension 2 Filter"),
            "Currency Code" = Field ("Currency Filter")
            ));
        }

        field(9; "First entry"; Boolean)
        {
            CalcFormula = exist (Customer where (Payments = const (0),
                                                 "No." = field ("No.")));
            FieldClass = FlowField;
            Caption = 'Specifies whether it is the customer''s first entry';
        }

        field(10; "Customer Balance"; Decimal)
        {
            FieldClass = FlowField;
            CalcFormula = lookup (Customer.Balance where ("No." = field ("No.")));
        }
    }
}

FlowFields overview
FlowFilter overview
CalcFormula property