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Introduction
FIGURE FM.3
The Collectible Mini Cars Products form, which allows data entry for all products in inventory
The Invoice form
frmInvoice, shown in Figure FM.4, demonstrates some more-advanced form concepts. Unlike
the other forms, the Invoice form contains a subform that uses a one-to-many relationship to join to
data on the main form; this means that there may be one or more records in the subform related to
the record displayed on the main form. In this example, an invoice sells one or more products to a
buyer.
This form also demonstrates calculations on the form. All the items in the Amount column have to
be totaled to yield the subtotal. All this is happening using fields in the Invoice Line Items (fsub-
SalesLineItems) subform.
The Invoice form also shows several other important techniques, including displaying values from
other forms. Each line item and payment can be deleted using a button. The bottom of the invoice
form contains buttons to create a new record a fill in any defaults, as well as to delete an unneeded
invoice and to display Search and Print dialog boxes.
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