There are two general
types of rule flows, simple and complex. A simple rule flow has a
single group of rule sets. All of the rule sets are run and output
is generated for each input record.
A complex rule flow
has at least three sections: Initial, Main, and Final. Rule sets in
the Initial section are run only when the first input record is processed.
Rule sets in the Main section are run for each input record. Rule
sets in the Final section are run after the last input record has
been processed by the rule sets in the Main section.
For complex rule flows,
you can specify BY-group terms. If you
specify BY-group terms, then SAS Decision Manager sorts
the input data by those terms, and results are calculated for each
group of input records that have the same value for all of the terms.
Output is generated for each BY group instead of for each input record.
Also, if you specify
BY-group terms, SAS Decision Manager adds two new sections
to the rule flow, Group Start and Group End. The rules sets in these
sections are run with the first and last input record in each BY group.
Note: You are not required to enter
rule sets into all of the sections in a rule flow.