Databases Reference
In-Depth Information
Create your rule in the normal way, and then click on the
Show Advanced Settings
icon; the double chevron next to the rule name circled in the following screenshot:
Next select
Advanced Mode
. This will expand the
IF
part of the rule, as we can see
in the following screenshot:
The circled part is called a
Pattern
and consists of two parts: the first is the type of
pattern that we wish to test for, and the second is the tests we want to apply to the
pattern. The rules engine supports the following patterns:
•
For each case where
: This is the
default
pattern, and is used to specify that the
rule should be applied to each fact where the test evaluates to true
There is a case where
: With this option, the rules will only be triggered once,
as long as there is at least one match
There is no case where
: With this option, the rule will be fired once if there
are no matches
Aggregate
: This option allows you to write rule conditions based on the
aggregate of more than one fact
•
•
•
When specifying the pattern, in addition to the pattern type, we need to specify
the
fact type
that we wish to apply the pattern to as well as a
variable
name that we
will use to reference the fact within the context of the rule (that is, within a test
and/or an action).
