The Specification Pattern
Business domains can be very different due to the different natures of each business. Some domains are more static and allow us to easily understand them and produce an efficient core model. However, some business domains are very dynamic, and it is difficult to get the gist and essence of the domain. Some problems require the code to change all the time. The first thing that comes to mind is to externalize business rules either in the form of configuration or in the form of database tables. Externalization to configs and databases works well when the business rules are simple, however, when the business rules are complex, such externalization is more complex and tends to generate more complexity. Nothing is better than code to express complex ideas. Good domain modeling via proper OO design is a very powerful way to map and describe domains.