A one-to-many linking relationship occurs
in linked tables when a single record in one table can be matched with many
records in another table. For example, you might link a customer table to an
orders table containing various products the customer has ordered. In your
report, the field values from the primary table are repeated for each new field
value in the lookup table.
Creating a subtotal on a field from the
primary table provides an incorrect result because the repeated values are
included in the calculation. You can avoid this problem by creating a running
total.
This concept can be demonstrated by using
the Customer and Orders tables from the Xtreme sample database.