IntroDatabases

Chapter 1

Database Systems

2

• After completing this chapter, you will be able to:

• Define the difference between data and information
• Describe what a database is, various types, and why they are valuable assets for

decision making

• Explain the importance of database design
• See how modern databases evolved from file systems
• Understand flaws in file system data management
• Outline the main components of the database system
• Describe the main functions of a database management system (DBMS)

Learning Objectives

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

3

• Characteristics of data in today’s world

• Ubiquitous (i.e., abundant, global, and everywhere)
• Pervasive (i.e., unescapable, prevalent, and persistent)

• Databases make data persistent and shareable in a secure way

• Specialized structures that allow computer-based systems to store, manage, and

retrieve data very quickly

Why Databases?

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

4

• Data consists of raw facts

• Not yet processed to reveal meaning to the end user
• Building blocks of information

• Information results from processing raw data to reveal meaning

• Requires context

• Bedrock of knowledge
• Should be accurate, relevant, and timely

Data versus Information

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

5

• Shared, integrated computer structure that stores data

• End-user data: raw facts of interest to end user
• Metadata: data about data, through which the end-user data is integrated and

managed
- Describes data characteristics and relationships

• Database management system (DBMS)

• Collection of programs

• Manages the database structure
• Controls access to data stored in the database

Introducing the Database

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

6

• Database management system (DBMS): intermediary between the user and the

database
• Enables data to be shared

• Presents the end user with an integrated view of data
• Provides more efficient and effective data management

• Improves sharing, security, integration, access, decision-making, productivity, etc.

Role and Advantages of the DBMS (1 of 2)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

6

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

Poll

In the video example above, I showed you an example of a database system. Have you experienced or witnessed a database system before?

• YES

• NO

7

Role and Advantages of the DBMS (2 of 2)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

8

• Single-user database: supports one user at a time

• Desktop database: single-user database on a personal computer

• Multiuser database: supports multiple users at the same time

• Workgroup databases: supports a small number of users or a specific department
• Enterprise database: supports many users across many departments

Types of Databases (1 of 5)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

9

• Classification by location

• Centralized database: data located at a single site
• Distributed database: data distributed across different sites

• Cloud database: created and maintained using cloud data services that provide

defined performance measures for the database

Types of Databases (2 of 5)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

10

• Classification by data type

• General-purpose database: contains a wide variety of data used in multiple disciplines
• Discipline-specific database: contains data focused on specific subject areas

• Operational database: designed to support a company’s day-to-day operations

Types of Databases (3 of 5)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

11

• Analytical database: stores historical data and business metrics used exclusively

for tactical or strategic decision making
• Data warehouse: stores data in a format optimized for decision support

• Online analytical processing (OLAP): tools for retrieving, processing, and modeling

data from the data warehouse

• Business intelligence: captures and processes business data to generate information

that support decision making

Types of Databases (4 of 5)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

12

• Databases can be classified to reflect the degree to which the data is structured

• Unstructured data exists in its original (raw) state
• Structured data results from formatting

- Structure is applied based on type of processing to be performed

• Semistructured data: processed to some extent

• Extensible Markup Language (XML)

• Represents data elements in textual format

Types of Databases (5 of 5)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

13

• Focuses on design of database structure that will be used to store and manage

end-user data
• Well-designed database: facilitates data management and generates accurate and

valuable information

• Poorly designed database: causes difficult-to-trace errors that may lead to poor

decision making

Why Database Design Is Important

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

14

• Manual file systems

• Accomplished through a system of file folders and filing cabinets

• Computerized file systems

• Data processing (DP) specialist created a computer-based system to track data and

produce required reports

• File system redux: modern end-user productivity tools

• Includes spreadsheet programs such as Microsoft Excel

Evolution of File System Data Processing (1 of 3)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

15

Evolution of File System Data Processing (2 of 3)

Table 1.2

Basic File Terminology

TERM

DEFINITION

Data

Raw facts, such as a telephone number, a birth date, a customer name, and a year-to-date
(YTD) sales value. Data has little meaning unless it has been organized in some logical
manner.

Field

A character or group of characters (alphabetic or numeric) that has a specific meaning. A field
is used to define and store data.

Record

A logically connected set of one or more fields that describes a person, place, or thing. For
example, the fields that constitute a record for a customer might consist of the customer’s
name, address, phone number, date of birth, credit limit, and unpaid balance.

File

A collection of related records. For example, a file might contain data about the students
currently enrolled at Gigantic University.

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

16

Evolution of File System Data Processing (3 of 3)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

17

• Problems with file systems challenge the types of information that can be

created from data as well as information accuracy
• Lengthy development times

• Difficulty of getting quick answers
• Complex system administration

• Lack of security and limited data sharing
• Extensive programming

Problems with File System Data Processing

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

18

• Structural dependence

• Access to a file is dependent on its own structure
• All file system programs are modified to conform to a new file structure

• Structural independence

• File structure is changed without affecting the application’s ability to access the data

Structural and Data Dependence (1 of 2)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

19

• Data dependence

• Data access changes when data storage characteristics change

• Data independence

• Data storage characteristics are changed without affecting the program’s ability to

access the data

• Practical significance of data dependence is the difference between logical and

physical format

Structural and Data Dependence (2 of 2)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

20

• Unnecessarily storing the same data at different places

• Islands of information (i.e., scattered data locations)
• Increases the probability of having different versions of the same data

Data Redundancy (1 of 2)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

21

• Possible results of uncontrolled data redundancy

• Poor data security
• Data inconsistency

• Data-entry errors
• Data integrity problems

Data Redundancy (2 of 2)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

22

• Develop when not all of the required changes in the redundant data are made

successfully
• Update anomalies

• Insertion anomalies
• Deletion anomalies

Data Anomalies

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

23

• Logically related data stored in a single logical data repository

• Physically distributed among multiple storage facilities
• DBMS eliminates most of file system’s data inconsistency, data anomaly, data

dependence, and structural dependence problems

• Current generation DBMS software

- Stores data structures, relationships between structures, and access paths
- Defines, stores, and manages all access paths and components

Database Systems (1 of 2)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

24

Database Systems (2 of 2)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

25

• Database system: organization of components that define and regulate the

collection, storage, management, and use of data within a database
environment
• Hardware

• Software
• People

• Procedures
• Data

The Database System Environment (1 of 2)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

26

The Database System Environment (2 of 2)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

27

• Data dictionary management

• Data dictionary: stores definitions of data elements and their relationships

• Data storage management

• Performance tuning ensures efficient performance

• Data transformation and presentation

• Data is formatted to conform to logical expectations

• Security management

• Enforces user security and data privacy

DBMS Functions (1 of 3)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

28

• Multiuser access control

• Sophisticated algorithms ensure that multiple users can access the database

concurrently without compromising its integrity

• Backup and recovery management

• Enables recovery of the database after a failure

• Data integrity management

• Minimizes redundancy and maximizes consistency

DBMS Functions (2 of 3)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

29

• Database access languages and application programming interfaces

• Query language: lets the user specify what must be done without having to specify

how

• Structured Query Language (SQL): de facto query language and data access standard

supported by the majority of DBMS vendors

• Database communication interfaces

• Accept end-user requests via multiple, different network environments

DBMS Functions (3 of 3)

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

30

• Disadvantages of database systems

• Increased costs
• Management complexity

• Maintaining currency
• Vendor dependence
• Frequent upgrade/replacement cycles

Managing the Database System: A Shift in Focus

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

31

Preparing for Your Database Professional Career

TABLE 1.3

DATABASE CAREER OPPORTUNITIES

JOB TITLE

DESCRIPTION

SAMPLE SKILLS REQUIRED

Database Developer

Create and maintain database-based
applications

Programming, database fundamentals, SQL

Database Designer

Design and maintain databases

Systems design, database design, SQL

Database
Administrator

Manage and maintain DBMS and
databases

Database fundamentals, SQL, vendor courses

Database Analyst

Develop databases for decision support
reporting

QL, query optimization, data warehouses

Database Architect

Design and implementation of database
environments (conceptual, logical, and
physical)

DBMS fundamentals, data modeling, SQL,
hardware knowledge, etc.

Database Consultant

Help companies leverage database
technologies to improve business
processes and achieve specific goals

Database fundamentals, data modeling,
database design, SQL, DBMS, hardware,
vendor-specific technologies, etc.

Database Security
Officer

Implement security policies for data
administration

DBMS fundamentals, database administration,
SQL, data security technologies, etc.

Cloud Computing
Data Architect

Design and implement the infrastructure
for next-generation cloud database
systems

Internet technologies, cloud storage
technologies, data security, performance tuning,
large databases, etc.

Data Scientist

Analyze large amounts of varied data to
generate insights, relationships, and
predictable behaviors

Data analysis, statistics, advanced mathematics,
SQL, programming, data mining, machine
learning, data visualization

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.

32

• Data consists of raw facts and is usually stored in a database

• Database design defines the database structure

- Can be classified according to the number of users, location, as well as data usage and

structure

• Databases evolved from manual and computerized file systems

- There are some limitations of file system data management
- DBMSs were developed to address the file system’s inherent weaknesses

Summary

© 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-

protected website for classroom use.