Chapter 3 Using Business Rules in a CDM

What is a business rule in CDM?

A business rule is a rule that your business follows. A business rule could be a government-imposed law, a customer requirement, or an internal guideline.

Starts as an observation

Business rules often start as simple observations, for example "customers call toll-free numbers to place orders." During the design process they develop into more detailed expressions, for example what information a customer supplies when placing an order or how much a customer can spend based on a credit limit.

Guides modeling

Business rules guide and document the creation of a model. For example, the rule "an employee belongs to only one division" can help you graphically build the link between an employee and a division.

Complements graphics

Business rules complement model graphics with information that is not easily represented graphically. For example, some rules specify physical concerns in the form of formulas and validation rules. These technical expressions do not have a graphical representation.

CDM to PDM generation

During generation of a Physical Data Model (PDM), or an Object-Oriented Model (OOM), from a CDM, the business rules transfer directly into the PDM or OOM. In the generated model, you further specify business rules to suit physical concerns.