HP Intelligent Management Center Standard Software Platform - Manual (Page 678)

For example, if you have chosen the Credit, Customer, Orders, and Orders
Details tables from the Xtreme sample database, the links tab shows the
tables linked as follows.
In this case, the links will be processed first between the Credit/Customer
tables, then between the Customer/Orders tables, and finally between the
Orders/Orders Details tables. The Links Order dialog box shows you this
default order and allows you to change the positions in the processing
hierarchy as you require.
Note:
Different link orders may result in different data sets returned for use in your
report. As well, link order has a significant effect on performance.
Linking options
Crystal Reports enables you to specify the type of join and type of link you
want to use when linking tables. You can also enforce the use of tables in
your joins. Joins and links indicates how linked fields in two tables are
compared when records are read. Join, enforce, and link options can be
specified in the Link Options dialog box. Using the various join enforcement
options can ensure that linked tables are included in the SQL query, even
when none of the fields in the table are used in the report.
678 Crystal Reports 2008 SP3 User's Guide
Understanding Databases 25
Linking tables