Chp 5 - Data Modeling

Chp 5 - Data Modeling

1. Data Models

   • Purpose: Describe structure of data
   • Components: Entities, relationships, attributes, cardinalities
     • Attributes
       • Define properties of classes
         • Include: Primary Key (PK), Foreign Key (FK)
     • Multiplicites
       • Define the cardinality of relationships
         • Examples: 1..1, 0.., 1..

2. UML Class Diagrams

   • Visualize database logic
   • Classes = Tables
     • Represents resources, events, people, or concepts
       • Examples: Cash, Sales, Employees, Budgets
     • Mapping to Relational Databases
       • Associations = Foreign Keys or Linking Tables
   • Associations = Relationships

3. Advanced Concepts

   • Generalization (Inheritance)
   • Aggregation vs. Composition

4. Business Rules

   • Types: Obligatory, prohibited, allowed
   • Enforcement: Strict, pre-override, post-override, guidelines

5. Decision Tables & Modeling

   • Combine multiple rules
   • Inputs > Conditions > Actions
   • Supports consistent decision-making