HP Intelligent Management Center Standard Software Platform - Manual (Page 686)

still include the join to TableA because it is enforced. Conversely, selecting
only from TableA with the same join condition will not cause the join to TableB
to be enforced.
Note:
For an explanation of from and to tables, see Link from and link to .
Enforced To
When you select this option, if the from table for the link is used, the link is
enforced. For example, if you create a link from TableA to TableB using
Enforce To and select only a field from TableA, the join to TableB will be
enforced, and the Select statement that is generated will include both tables.
Note:
For an explanation of from and to tables, see Link from and link to .
Enforced Both
When you select this option, if either the from table or the to table for this
link is used, the link is enforced.
Equal [=] link
The result set from an Equal link includes all the records where the linked
field value in both tables is an exact match. In the following example, the
Customer table is linked to the Orders table by the Customer ID field. When
the program finds a Customer ID in the Orders table that matches a Customer
ID in the Customer table, it displays information for the corresponding records
in both tables.
SQL uses the following syntax to describe an Equal link:
SELECT Customer.'Customer ID',
Customer.'Customer Name',
Orders.'Order Amount'
FROM 'Customer' Customer,
'Orders' Orders
WHERE Customer.Customer ID =
Orders.Customer ID
686 Crystal Reports 2008 SP3 User's Guide
Understanding Databases 25
Linking tables