IS201: Database theory - Data models

Data model

An abstraction of a complex real-world environment with a well-defined scope and boundaries to be systematically addressed and is the first step in designing a database

Business rules

1st step in data modelling, brief and precise descriptions of a policy, procedure or principle

Why business rules are essential to database design

• Standardize company’s view of data

• Serve as communication tool between users and designers

• Helps designer understand data’s nature, role and scope

• Help designer understand business processes

• Enables appropriate relationship rules, constrains and accurate data models

Elements of data models

• Entity of which data will be collected

• Attribute which describes the entity

• Relationship: association among entities

• Constraint placed on the data

Evolution of data models

1. Hierarchical and network models

2. Relational model

3. Entity relationship model

4. object-oriented model

5. object/relational model

6. Big data and NoSQL models