You link tables so that records from one
table will match related records from another table. For example, if you
activate an Orders table and a Customers table, you link the tables so that
each order (from the Orders table) can be matched up with the customer (from
the Customer table) that made the order.
The fields used to link two tables must
have the same data type. For example, you can link a string field in one table
to a string field in another table, or a numeric field in one table to a
numeric field in another table, but you cannot link a numeric field in one
table to a string field in another table
When you link, you are using a field that
is common to both tables.
Crystal Reports uses the link
to match up records from one table with those from the other.