Course Contents

Week Topic

1 Overview of Database Design Introduction to Databases Design Database Management System (DBMS) Database Life Cycle (DBLC) Database Components

Week 1 Learning Objectives

Students will be able to:

explain the purpose of database system

define main components of database environment

explain the functions of DBMS define main phases of database design

in DBLC

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Data Storage Approaches

File-Based System

Database Approach

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Files and File Systems

Shared collection of logically related data (and a description of this data), designed to meet the information needs of an organization.

System catalogue (metadata) provides description of data to enable program data independence.

Logically related data comprises entities, attributes, and relationships of an organizations information.

Database Systems

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Database Systems

Database system consists of logically related data stored in a single logical data repository May be physically distributed among multiple

storage facilities

Database Management System (DBMS) eliminates most of file systems problems

Current generation stores data structures, relationships between structures, access paths Takes care of defining, storing, managing all access

paths and components

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Database Systems

Why Database?

Arose because:

No provision for security and integrity, no recovery, no provision for sharing

Definition of data was embedded in application programs, rather than being stored separately and independently.

No control over access and manipulation of data beyond that imposed by application programs.

To be effective:

Database and the Database Management System (DBMS) is introduced.

DBMS Environment

ANSI-SPARC Three-Level Architecture

DBMS Environment

Differences between the three-Level

DBMS Environment

A real-world situation or

problem

Thinks about

Makes comparisons

A system that helps to understand the real-world situation

Database Management System (DBMS)

A software system that enables users to define, create, maintain, and control access to the database.

(Database) application program: a computer program that interacts with database by issuing an appropriate request (SQL statement) to the DBMS.

Database Management System (DBMS)

Components of a DBMS

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Database Lifecycle (DBLC)

Note:

Section 9 -> 10

Will be focused

Main activities in DBLC

Stages Main Activities

Database Planning Planning how the stages of the lifecycle can be realized most efficiently and effectively.

System Definition Specifying the scope and boundaries of database system.

Requirement collection and analysis

Collection and analysis of the requirements for the new database system.

Database design Conceptual, logical and physical design of the database.

DBMS selection Selecting a suitable DBMS for the database system.

Application design Design the user interface and the application program that use and process the database.

Prototyping Building a working model of the database system.

Implementation Creating the physical database definitions and the application programs.

Data conversion and loading Loading data from old system to the new system.

Testing Database system is tested for errors and validated against the requirements specified by the user.

Operational maintenance Database system is fully implemented and continuously monitored.

Parallel activities in the DBLC and SDLC

Why Database Design is Important?

Database design focuses on design of database structure used for end-user data Designer must identify databases expected use

Well-designed database: Facilitates data management

Generates accurate and valuable information

Poorly designed database: Causes difficult-to-trace errors

Increase costs, degrade performances

Database Design

Process of creating a design for a database that will support the enterprises mission statement and mission objectives for the required database system.

The design is made up of three (3) main phases: conceptual, logical, and physical.

A specific approach and model are applied for designing a proper database system.

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Database Design Approach

Main approaches include:

Top-down, Bottom-up, Inside-out, Mixed

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Database Model

Main purposes of data modeling include:

to assist in understanding the meaning (semantics) of the data;

to facilitate communication about the information requirements.

Building data model requires answering questions about entities, relationships, and attributes.

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Database Model - Example

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Database Model - Exercise

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Identify data to be captured !!!, Make a list

END OF TOPIC 1

Questions?

Thanks