Navision contains fields called FlowFields. These are fields whose contents are constantly changing - the system calculates the value of the contents of a FlowField each time you open the window containing the field. FlowFilters are used to determine how much the system will include when it calculates the contents of FlowFields.
FlowFields are used to display amounts and quantities that must always be up-to-date. The calculation can be based on information in tables other than the one that contains the field.
An example of a FlowField is the Balance field, which is in the G/L Account table. You can see the field on the G/L Account Card, but the information on which the balance is based is taken from the Entry table, which contains posted G/L entries. Similarly, the contents of the Balance field for a customer is based on information in the Cust. Ledger Entry table, and so on.
This is because the only information you can change in G/L Account, Customer, Vendor and Item tables is the basic information such as addresses, codes, and so on. Financial information in these tables is displayed in FlowFields, but you cannot change it directly. This information is calculated from information in ledger entry tables. You can change information in the ledger entry tables by posting entries.
The system already knows how to calculate the contents of FlowFields. But with the View, FlowFilter function you can temporarily limit which entries in the other tables should be included in the calculation. You do this by defining a FlowFilter in the window in which the result of the calculation will be displayed (for example, the result of the calculation for the Balance field will appear on the customer card). The system will use the filter in the ledger entry table (in this case the Customer Ledger Entry table), when it totals the ledger entries.