Chapter 3 Entity Relationship Model
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This document discusses database design using Entity Relationship Diagrams (ERDs). It covers how to draw ERDs using Chen's Model and Crow's Foot notations and define the basic elements of ERDs. Conversion rules are presented to convert ERDs into relational tables for one-to-one, one-to-many, and many-to-many relationships. An example is given to demonstrate drawing an ERD for a company database and converting it into relational tables.
Chapter 3 Entity Relationship Model
- 1. DFC2033
- 2. Course Learning Outcome — CLO1:Apply the fundamentals concepts of database management and relational data model to create a database based on an organization’s requirements. (C3, PLO1) — CLO2: Develop a database using a concurrency control and data recovery technique based on Database Management System (DBMS). (P3, C3, PLO2, PLO1)
- 3. Learning Outcome — Apply Entity Relationship Diagrams (ERD) in database development — Define the three basic elements of ERD: entity types, relationship, attributes and keys. — Use Chen’s Model to draw ERD — Use Crow’s Foot notations to draw ERD. — Design E-R model based on a given scenario. — Describe the basic conversion rules to convert ERD into relational tables: a. One to one relationship b. One to many relationship c. Many to many relationship — Apply the conversion rules to convert a given ERD into relational tables
- 8. ERD: Crows Foot Model
- 22. 1
- 36. Exercise A company database needs to store information about employees (identified by ssn, with salary and phone as attributes), departments (identified by dno, with dname and budget as attributes), and children of employees (with name and age as attributes).
- 37. Analyze the problem/case — A company database needs to store information about employees (identified by ssn, with salary and phone as attributes), departments (identified by dno, with dname and budget as attributes), and children of employees (with name and age as attributes). — Employees work in departments; a child must be identified uniquely by name when the parent (who is an employee; assume that only one parent works for the company) is known. — Draw an ER diagram that captures this information.
- 39. Apply the conversion rules to convert a given ERD into relational tables Departments Child Employees name age phone ssn salary Dependent budget dno dname Works_In