ER Model Concepts

Entities, Attributes and Relationships

The relational design procedure gives a structured approach to modeling an information system’s data and the business rules for that particular data. After you learn the fundamentals of this process and you should be able to take the information learned from the requirements gathered for the system (like as the information presented in the case study) and simply design a database.

The three key mechanism used in relational database design that are entities, attributes and relationships are outlined in following Table which are given below.

THE THREE KEY COMPONENTS USED IN RELATIONAL DATABASE DESIGN.

Design Component            Implemented in SQL Server              Examples

Entities                                  Tables                                               Student, Course

Attributes                              Columns in a Table                             Student’s Name,
                                            Course number

Relationships                         Primary/Foreign key                            Teacher to Class
                                           Columns or Tables         

         
The upcoming subsections describe every component in more detail.  The chapter then discusses in common terms how these parts are implemented in SQL Server.