Operation Manual

Understanding Databases
Databases overview
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Crystal Reports User’s Guide 485
Often, data in two different tables can be related by a common field. For
example, a Customers table will have a Customer ID for each customer, and
an Orders table will have the Customer ID of each customer who placed an
order, demonstrating a relationship between tables. The two tables can be
linked by a common field see “Linking tables” on page 489.
The following diagram displays how two tables can have a relationship:
Aliases
For a variety of reasons, database names and locations get changed. If you
create a report, then change the name or location of a table or file, the Report
Designer must be able to find the new name or location. This is especially
important when you create formulas in your report that access a table that has
been renamed or moved. To fix the reference for a single field would not be
difficult, but to find every formula that uses that field could be a difficult and
time consuming task.