If you look back in the history of software, it has always been based on abstraction of the real world. The real world, however, is a place of continuous change. Most business applications have been written to support business processes that are fairly stable, hence providing the repeatability that is needed to perform tasks efficiently. Certain industries like Insurance and Banking are faced with business rules that need constant changes. This is because of a variety of factors like the nature of the business, compliance to local and global policies, government regulations etc.

Imagine a piece of code which represents business rules. As part of the evolution of software engineering, modularization techniques were introduced to make this piece of code re-usable,and easier to maintain.In the SAP ABAP world, a familiar technique was the use of function modules - certain input parameters were passed to the function module and certain output values were determined – much like the use of simple real life tools like the calculator. Business rules could be coded within this function module and could be called from other programs.