lecture 03 entity-relationship diagram. chapter outline
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Lecture 03
Entity-Relationship Diagram
Chapter Outline
Overview of Database Design Process
Overview of Database Design Process
Example COMPANY Database
Example COMPANY Database(Contd.)
ER Model Concepts
Types of Attributes (1)
Types of Attributes (2)
Example of a composite attribute
Entity Types and Key Attributes (1)
Entity Types and Key Attributes (2)
Displaying an Entity type
Entity Type CAR with two keys and acorresponding Entity Set
Entity Set
Initial Design of Entity Types for theCOMPANY Database Schema
Initial Design of Entity Types:EMPLOYEE, DEPARTMENT, PROJECT,
DEPENDENT
Refining the initial design by introducing
relationships
Relationships and Relationship Types (1)
Relationship type vs. relationship set (1)
Relationship type vs. relationship set (2)
Refining the COMPANY databaseschema by introducing relationships
Discussion on Relationship Types
Recursive Relationship Type
Weak Entity Types
Constraints on Relationships
Recursive Relationship Type is: SUPERVISION
(participation role names are shown)
Attributes of Relationship types
Notation for Constraints onRelationships
Alternative (min, max) notation forrelationship structural constraints:
Alternative diagrammatic notation
Summary of notation for ER diagrams
Extended Entity-Relationship (EER)Model (in next chapter)
Chapter Summary