Data Modeling and Conceptual Design

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Data Modeling and Conceptual Design

• ICS 22 Database Systems
• Lecture 3

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Data Modeling Using the
Entity-Relationship (ER) Data Model

• Phases of Database Design
• Conceptual Design
• E-R model

Steps in DB Design
Requirements Definition
Data-oriented approach - because data are more
stable than the functions (or processes) in an
organization.
Develop ER Model
Normalized Tables
Design Application
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Database Design and Conceptual Data Model

• Analogous to analysis phase of software
  development
• Requirement Collection and Analysis
• - Designers interview database users to
  understand and document data requirements.
• Functional Requirements
• - User defined operations to be applied on the
  database

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Database Design and Conceptual Data Model (contd.)

• Conceptual Design
• -Conceptual schema a permanent description of
  database specifications.
• - Capture the semantics of the data description
  of data, constraints, relationships
• - No storage details needed

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HISTORY OF DATA MODELS

• Description in high-level model
• - Close to the user' view of mini-world
• - Abstract concepts
• - Means of communication between the
  non-technical users and the developer
• - Allows user to influence design and is
  independent of any particular DBMS.
• Entity Relationship Data Model
• - developed by Peter Chen (1983)
• - basis for ANSI IRDS (Dolk Kirsch, 1987
  Winkler 1989)

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Coincidences between the ER Model and the Surface
Structure of English(P. Chen, 1983)
Symbol
ER Meaning
English Equivalent
Entity
Noun
Verb
Relationship
Attribute of Entity Relationship
Adjective
Adverb