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Case Study : Modelling tax rules with Rulette — Part Two
How Rulette simplifies managing changes to your business rules
In part one of this series, we looked at ground-up modelling, storage, and evaluation of taxation rules using Rulette. By the end of that article, we had a Rulette based system storing all rules in MySQL and we were able to evaluate the applicable tax values for various combination of rule inputs. In this post, we will look at how we can evolve this rule system to accommodate more evaluation criteria.
Rules are meant to change
Let us consider that the government changes the tax law to state that taxes to be paid on a sale now depend not only on the state where the manufacturer is located but also on the state where the customer is located. And this change of rules will come into affect a week from now, i.e. May 6, 2020.
Everyone goes into a huddle again, and out comes an updated excel sheet which has lots more rules than our previous sheet (because we need to model all to-from combinations of states). e.g
becomes
The other part of the problem is that the new rule set should only become live at 00:00 on May 6. There should ideally be no downtime to the system.
