IM L 3

• DECLARATIVE - A business rule is a statement of policy, not how policy

  is enforced or conducted; the rule does not describe a process or implementation, but rather describes what a process validates.
• PRECISE - The rule must have only one interpretation among all interested people, and Its meaning must be clear.
• ATOMIC - A business rule marks one statement, not several
• CONSISTENT - A business rule must be internally consistent (that is, not contain conflicting statements) and must be consistent with (and not contradict) other rules
• EXPRESSIBLE - A business rule must be able to be stated in natural language, but it will be stated in a structured natural language so that there is no misinterpretation
• DISTINCT - Business rules are not redundant, but a business rule may refer to other rules (especially to definitions).
• BUSINESS-ORIENTED - A business rule is stated in terms businesspeople can understand, and because it is a statement of business policy, only businesspeople can modify or invalidate a rule; thus, a business rule is owned by the business
• Entities:

  — Entity instance - person, place, object, event, concept (often corresponds to a row in a table)

  — Entity Type - collection of entities (often corresponds to a table)
• Relationships:

  — Relationship instance - link between entities (corresponds to primary key-foreign key equivalencies in related tables)

  — Relationship type - category of relationship...link between entity types
• Attribute - property or characteristic of an entity or relationship type (often corresponds to a field in a table)