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Introduction

Database Design

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What is a Database

Databasecollection of organized data

Legacy databasethe database is old and been

in the company for quite some time

Examples of databases:Address books

Telephone directory

Library information

Bookstores Finance softwares

maps

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OLTP and OLAP

Online Transaction Processing(OLTP)

Database used to process data in a regular basis

Examples: grading system, sales, reservation

Online Analytical Processing(OLAP)

Supply end users with response to queries being

submitted

Concerned with bulk data loads

Decision Support Systems and Data Warehouses

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Database Environment

Mainframe environmentconsists of powerfulmainframe computer that allowed multiple user

connections. Multiple terminals are networked to

the main computer

Client/server environmentinvolves a main

computer , called the server, and one or more

personal computers are connected into it

Internet computing environmentrelies on the

internet for networks, the server is called the Web

Server

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Where Does a Database

Originate?

Business rules

Business processes

Data

Analysis Entities

Attributes

Re-engineering

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Business Rules

It affects the business in many ways

Tells how data is created, stored, and retrieved,

and manipulated

Categories of business rules:-database oriented

-application oriented

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Business Processes

Daily/timed activities of the company

Can be manual or automated

Example:

1. Order is received from customer2. Inventory is checked for availability

3. Customers order if confirmed

4. Warehouse is contacted

5. Product and invoice are shipped to the

customer

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Information and Data

Informationknowledge of something

Datainformation related to the organization

Types of data:

Static/historical

accessed only when needed Dynamic/transactionalused more often

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Requirements Analysis

Analyzing the needs of a business

Rules and process are considered aside from

data

Some of basic information needed: Objectives and goals pertaining to the system

Proposed requirements

Business process and rules

Documents of current information

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Entities and Attributes

Entities

Business object that represent a group, or

category of data

Examples:titles, topics

Attributes

Sub group of information within an entity

Example: within a book title there can be theactual title, the publisher, and author

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Business process re-engineering

Task of reworking process in order to streamlinethe operations

Redesigning the entire system

Improvement of methods

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Elements of a Database

Schema

Schema objects

Tables

Fields and columns Records or rows

Keys

Relationships

Data types

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Database Schema

Schemagroup of related objects in a database Conceptual/logical model

Internal/physical model

External/view model

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Tables

Primary unit of physical storage in the database

Types of data:

Data tables

Join tables

Subset tables

Validation tables

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Columns

Category of information in the database

Represents related part of a table

Smallest logical structure

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Rows

Collection of all columns in a table associatedwith a single occurrence

Single record in a table

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Data Types

Alphanumeric

Numeric

Date and Time

Boolean Character Large Objects

Binary Large Objects

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Database Integrity

Insurance of accurate data in database

Constraintsvalidate the values of the data

Referential integrityprocess of ensuring that

data is consistent between related tables

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Relationships

Relationships reduce data redundancy

Normalizationprocess of reducing data

redundancy

Types of relationships:

One-one

One-many

Many-many

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Design Methodology

Process of designing a database with a plan

Advantages:

Step by step guide

Minimal trial and error

Easier documentation

Easier to modify the database

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Application Design

Creating an interface for the end user throughwhich the database can be accessed

Consists of set of forms that allow the end user to

manipulate data

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Characteristics of a good

database

Storage needs met

Available data

Secured data

Accurate and easy to manageAcceptable performance to the user

Minimal redundant data