Hi Rob,
another approach we're considering to version rulesets used to perform
mortgage risk assessment looks roughly as follows:
- each of the rulesets is versioned as a whole (i. e. compile all *.drl
pertaining to a ruleset into a *.pkg file and give this *.pkg a version
number).
- the scoring service is aware that rules evolve and selects the ruleset
which fits the "processing date". the processing date is part of the
scoring request we send to the service
- scoring service loads selected ruleset and performs risk assessment,
sending back risk indicators
We don't like the idea of time-dependent rules very much, as this
introduces *versioning* into the rule source code itself, which is
additional complexity we'd like to keep out of the *.drl files. We want
to be able to drop old rules from the source code once they are not
valid any more, but still have them compiled with a version number
somewhere in a repository, just in case a mortgage application needs
re-scoring based on an older version of the rules. We can afford this
rather "static" approach as our rules don't change too often (like a few
rules every week or two).
Best regards
Ansgar
Am 24.08.2011 21:42, schrieb Rob Fisher:
Looking for best practice recommendations around the versioning of a
rule. Our application will have 50-60 rule sets comprised of up to 70
rules each. The activation of many of the rules will be based on a
processing date (inserted fact attribute). The application processing
date can be prior, equal, or after the system date.
For example, 2 rules, with slightly different logic
Eligibility rule version 1
//to be potentially activated for application processing time period
prior to 2011
When
Car(color = "blue")
Then
Terms(eligible = "yes")
Eligibility rule version 2
//to be potentially activated for application processing time period
2011 and forward
When
Car(color = "blue", type="coupe")
Then
Terms(eligible = "yes")
We've come up with a couple of different ways to handle this:
1. Add Date logic to LHS of the rule . i.e add
"Control(processingDate < '01/01/2011')" to 1st rule and
"Control(processingDate >= '01/01/2011')" to 2^nd rule. First
rule would activate with processing date = 12/31/2010 and 2^nd
rule would activate with processing date = 07/31/2011. When
originally authored, first rule would be written without date
logic. When 2^nd rule is authored, data logic will need to get
added to both.
2. We explored a way of setting the session clock to the processing
date and using the 'date-effective' and 'date-expires'
attributes to do the filtering. i.e. 1^st rule is effective
until 12/31/2010 and 2^nd rule is effective from 01/01/2011 to
12/31/9999. However, we could only figure out how to do this
with a stateful knowledge session. Is it possible in a Stateless?
3. We added metadata to the rules (@EffectiveDate and
@ExpirationDate), and using agendafilter, we compared processing
date to the metadata and return true or false dependent on
comparison.
What are your opinions on these three methods? What are other options?
Thanks
Rob
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