Operation Manual

Understanding Databases
Linking tables
25
504 Crystal Reports User’s Guide
Not Enforced
When you select this option, the link you’ve created is used only if it’s
explicitly required by the Select statement. Your users can create reports
based on the selected tables without restriction (that is, without enforcement
based on other tables). This is the default option.
Enforced From
When you select this option, if the to table for the link is used, the link is
enforced. For example, if you create a link from TableA to TableB using Enforce
From and select only a field from TableB, the Select statement will 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” on
page 490.
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” on
page 490.
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.
60 16 24580.50
62 19 7911.80
63 28 19766.20
63 32 12763.95
64 14 8233.50
65
66
25 10320.87
Customer Table Orders Table Orders Table
Customer ID Order ID Order Amount