ch01

Chapter 1

Introduction to Database Management

Chapter 1. Introduction to Database Management

Initial Definitions

• Database: a collection of persistent and interrelated data that are shared

by many users and applications

• Data: symbolically represented raw facts (i.e., numeric, textual,

graphical, and often pictorial encoding) about things, people, and events

observed in the real world

• Information: data transformed (e.g., aggregated, sorted, clustered,

sampled, and depicted) for a specific purpose

MIS 6326: Database Management 1


Database Characteristics

• Persistent

– data residing on stable storage, not a temporary storage such as computer memory (Textbook’sdefinition)← relevance of intended usage

– Stored data can subsequently be removed from the database only by some explicit request to thedatabase management system, not as a side effect of a program execution. (C.J. Date’s definition)

– Lasts a long time (not transient). (e.x., birth date vs. age)

• Interrelated

– separate data units connected to provide a broader view

– entity: cluster of data about a topic (customer, student, loan)

– relationship: connection among entities

• Shared

– by multiple applications and users (maybe at the same time)

– a database as a common information repository and information exchange platform (file processingvs. database approaches)



An Example: University Database

University Database

Registration

Grade

Recording

Faculty

Assignment

Course

Scheduling

Entities:

students, faculty, courses,

offerings, enrollments

Relationships:

faculty teach offerings,

students enroll in

offerings, offerings made

of courses, ...



Database Management System (DBMS)

• Collection of components that support data acquisition,

dissemination, storage, maintenance, retrieval, and

formatting (Database Software)

• Major part of information technology infrastructure

– Enterprise DBMS: supporting mission critical information systems

– Desktop DBMS: for small and end-user databases

– Embedded DBMS: resides in a separate system or device such as

PDA



Features of DBMS

• Data Definition: Database Creation

• Nonprocedural Access: Data Retrieval

• Application Development: Data Input Screens, Reports,

User-Friendly Environments

• Procedural Language Interface: Serious IS Development

• Transaction Processing: Database Administration

• Database Tuning: Database Administration



Data Definition

• Define structures of data in a database: Tables and references

• SQL CREATE TABLE statement

Table: a two-dimensional

arrangement of data

SQL: an industry standard

database language

for data definition,

data manipulation, and

database control.

create table Offering (

OfferNo integer not null,

CourseNo char(6) not null,

OffTerm char(6) not null,

OffYear integer not null,

OffLocation varchar(30) null,

OffTime varchar(10) null,

FacSSN char(11) null,

OffDays char(4) null,

constraint OfferingPK primary key (OfferNo),

constraint CourseFK foreign key (CourseNo) references Course,

constraint FacultyFK foreign key (FacSSN) references Faculty )

• Graphical tools



Data Definition: A Graphical Tool (MS Access)



A Modeling Language (i.e., Tool) for Data Definition

Student

PK StdNo

StdFirstName

StdLastName

StdCity

StdState

StdZip

StdMajor

StdClass

StdGPA

Offering

PK OfferNo

FK2 CourseNo

FK1 FacNo

OffLocation

OffYear

OffTerm

OffDay

OffTime

Faculty

PK FacNo

FacFirstName

FacLastName

FacCity

FacState

FacZip

FacDept

FacRank

FacSalary

FK1 FacSupervisor

FacHireDate

Enrollment

PK,FK1 StdNo

PK,FK2 OfferNo

EnrGrade

Course

PK CourseNo

CrsDesc

CrsUnits

Registers

Accepts

Teaches

Supervises

has



Nonprocedural Access: Query

• Query: Request for data to answer a question

• Indicate what parts of database to retrieve, not how to retrieve

them (not the procedural details)

• Improve productivity and improve accessibility

• SQL SELECT statement

select StdFirstName, StdLastName, StdCity, OfferNo, EnrGrade

from enrollment, student

where enrollment.StdSSN = student.StdSSN

and EnrGrade > 3.5

• Graphical tools



Nonprocedural Access: A Graphical Tool (MS Access)



Application Development

• Form: formatted document for data entry and display

• Report: formatted document for display

• Use of nonprocedural access to specify data

requirements of forms and reports

– “View”: Standard SQL

– Stored “Query”: Access



A Sample Data Entry Form (MS Access)



A Sample Report Form (MS Access)



Procedural Language Interface

• Combine procedural language with nonprocedural access

• Why

– Batch processing

– Customization and automation

– Performance improvement

• Modes of Connection between a Language and a Database Software

– Direct API calls

– Middleware: ODBC, JDBC

• Examples

– Java or Visual Basic programming over a database

– Web database publishing



Transaction Processing

• Transaction: a unit of data modification work that

should be reliably processed

• Control simultaneous users

• Recover from failures

Database Tuning

• Analyze and improve database system performance



Database Technology Evolution

Era Generation Orientation Major Features

1960s 1st File File structures and proprietary

program interfaces

1970s 2nd Network

Navigation

Networks and hierarchies

of related records, standard

program interfaces

1980s 3rd Relational Non-procedural languages,

optimization, transaction

processing

1990s to 2000s 4th Object Multi-media, active,

distributed processing, XML

enabled, data warehouse

processing, cloud computing



DBMS Marketplace

• Enterprise DBMS

– Oracle: dominates in Unix; strong in Windows

– SQL Server: strong in Windows

– DB2: dominates in mainframe

– Teradata: as a data warehouse platform

– Significant open source systems: MySQL, Firebird, PostgreSQL

• Desktop DBMS

– Access: dominates



Worldwide Market Share in 2004 & 2005

Source: IDC, May 2006

DB SW Rev. ($M) Share (%) Growth (%)Vendor 2004 2005 2004 2005 2004–2005

Oracle 5,982.4 6,494.7 45.0 44.6 8.6IBM 2,923.0 3,113.0 22.0 21.4 6.5Microsoft 2,013.0 2,441.5 15.1 16.8 21.3Sybase 470.9 502.6 3.5 3.5 6.7NCR/Teradata 390.0 423.0 2.9 2.9 8.5Others 1,528.9 1,590.8 11.5 10.9 4.1

Total 13,308.1 14,464.6 9.4

Source: Gartner Dataquest, May 2006

DB SW Rev. ($M) Share (%) Growth (%)Vendor 2004 2005 2004 2005 2004–2005

Oracle 6,234.1 6,721.1 48.9 48.6 7.8IBM 2,860.4 3,040.7 22.4 22.0 6.3Microsoft 1,777.9 2,073.2 13.9 15.0 16.6NCR/Teradata 412.1 440.7 3.2 3.2 6.9Sybase 382.8 407.0 3.0 2.9 6.3Others 1,090.4 1,134.7 8.5 8.2 4.1

Total 12,757.8 13,817.4 8.3

Open Source DatabaseDevelopment Survey (Source:Evans Data, January 2005)

DB Software Responses

MySQL 53%Firebird 52%PostgreSQL 15%Berkeley DB 4%GNU SQL 3%SAP DB 1%Others 6%



Worldwide Market Share in 2006

Source: Gartner, June 2007

• Yearly Growth: 14% ($15.2 billion in sales)

• Oracle: 47.1% market share ($7.2 billion in sales), 14.9% revenue growth

• IBM: 21.1% market share ($3.2 billion in sales), 8.8% revenue growth

• Microsoft: 17.4% market share ($2.65 billion in sales), 28% revenue growth

• Teradata: approx. 4% market share ($494 million in sales), 5.7% revenue growth

• Sybase: less than 4% market share ($488 million in sales), less than 5% revenue growth



Worldwide Market Share in 2007

Source: IDC, June 2008

• Yearly Growth: 12.6% ($18.8 billion in sales in 2007 up from $16.7 billion in 2006)

• Oracle: 44.3% market share ($8.3 billion in sales), 13.3% revenue growth

• IBM: 21.0% market share ($4 billion in sales), 13.3% revenue growth

• Microsoft: 18.5% market share ($3.5 billion in sales), 14% revenue growth

• Sybase: 3.5% market share

• Teradata: 3.3% market share

• Others: 9.4%



Data Independence

• Definition: A database should have an identity separate from

the applications that use it.

• To alleviate problems with software maintenance

– Software maintenance is a part (50%) of information system budgets.

– To reduce impact of changes by separating database description from

applications

– To change database definition with minimal effect on applications that

use the database

• Three Schema Architecture

– for compartmentalizing database descriptions in order to achieve data

independence.



Three Schema Architecture

View 1 View 2 View n

ConceptualSchema

InternalSchema

External

Level

Conceptual

Level

Internal

Level

External toConceptualMappings

Conceptualto InternalMappings



Differences among Levels

• External

– Faculty Assignment Form View: data required for the form in Slide 12

– Faculty Work Load Report View: data required for the report in Slide 13

• Conceptual: the whole database from users’ and DB

developers’ point of view (e.g., Slide 8)

• Internal

– Files needed to store the tables

– Extra files to improve performance

– The whole database from the point of view of hardware and physical

processing



Client-Server Architecture

Database

Databaseserver

a) Client-server processing with database server

Database

Database

serverMiddleware

server

b) Client-server processing with middleware and database servers



Parallel Database Architecture

M

N

...

P P P...

M M M

N

...

P P P...

M M

(a) SD (b) SN

Legend

P: processor

M: memory

N: high-speed network

SD: shared disk

SN: shared nothing



Distributed Database Architecture

Client Server Server

DatabaseDatabase

Client

Client

Client

Denver London

Server

Database

Tokyo

Client

Client



Cloud Computing

Server Server

DatabaseDatabase

Server

Database

• no initial product licensing costs and no hosting requirements

• web-based interfaces

• dynamic resource allocation



Database Specialists

• Database administrator (DBA)

– More technical

– DBMS specific skills

• Data administrator

– Less technical

– Planning role

– Information resource management



DBA Responsibilities

Technical Non-technical

Designing conceptual schemas Setting database standards

Designing internal schemas Devising training materials

Monitoring database performance Promoting benefits of

databasesSelecting and evaluating database

software

Consulting with users

Managing security for database usage Planning new databases

Troubleshooting database problems


ch01

Documents

database management

database control

parts of database

database administration

database approaches

applications data

interrelated data

data manipulation