Mainframes 360
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Friday, December 25, 2009

Decision-making constructs

Q. What are business rules?
A business-rule is a representation of a decision-making logic. For example in a bank, the loan-officer decides to issue you a personal loan based on your credit-rating and your annual pay. This simple business rule could be described as,
Business rules can get complex. Every house-hold has an electricity, water and gas connection. I hail from Mumbai city, where Reliance Energy is responsible for electricity distribution. Here is a picture of my electricity bill.

  Bill-01  Bill-02

The energy company has divided the tariff into slabs. The ceiling for the first slab is 100 units. Say, you’ve consumed 150 units this month. The Energy charge for the first hundred units will be at the rate 296 paise/unit. The energy charge for the excess fifty units will be at the rate 556 paise/unit. The business rule employed by the energy company to calculate the bill could be described as, In India, the government authorities(RTO) issues a driver’s license. The minimum age is 18 years for all vehicles. The driver must pass the driving test. This business rule could be described as,
In a nutshell, any industry or business has conditions or constraints based on which decisions are made, for example issuing a bank loan, under-writing an insurance policy, billing of a customer etc. These are called business conditions or rules.
Q. How to code business rules in Cobol?
When companies started automating their business processes and computerization took place, business rules started being written in software applications. The two control structures
IF-THEN-ELSE and EVALUATE are used to code business rules in the Cobol language.

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