LESSON-2

2. Business Rules Versus Object Technology 

How to express different type of rules in E-R diagram?  

Many business rules as constraints (implicitly or explicitly) are deployed on classes, instances, attributes, operations, relationships, cardinality, order, association roles, etc. 

We have also deployed semantics constraints among subclasses; overlapping, disjoint, etc. UML allows the use
 of specific keywords within braces, say, {disjoint}, {overlapping}, {ordered}, and placing them close to the constraints apply to. 

But if you can define a business rule using such a predefined UML constraint, define it in plain English,
or in some other languages such as formal language.