Transcript An Introduction to Information Systems

Fundamentals of
Business Information Systems
2nd Edition
By Ralph Stair, George Reynolds
and Thomas Chesney
Chapter 3
Organizing Data
and Information
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Principles
• Data management and modelling are key aspects of
organising data and information.
• A well-designed and well-managed database is central to
almost all information systems and is an extremely
valuable tool in supporting decision making.
• The number and type of database applications will
continue to evolve and yield real business benefits.
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Database
• The centre of almost every information system
• The most common database is the relational
database
• A relational database is a series of related
tables, stored together with a minimum of
duplication to achieve consistent and
controlled pool of data.
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Relational Database
A relational database is made up of a number of tables
A table is made up of a number of records
Each record is made up of a number of fields
In loose terms, each table stores the data about someone or
something of interest to the firm, known as an entity. Customer is
an example
• The fields are the specific items of data stored about an entity
(name, data of birth, address, etc.)
• A record collects all the data about one specific entity, the
customer John Smith for example
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•
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For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Keys
• Each record must be unique in some way
• The primary key is a field that is defined to be
unique for each entity
• Student ID, Exam ID and Library ID are all primary
keys that uniquely identify you
• Primary keys are used to join tables:
‘Post’ a primary key into another table to join the
two (see Figure 5.1 and 5.2)
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Database Design
• A database design is also known as a data model or a
database schema
• It is a list of all the tables in the database, along with all the
fields, with any primary and foreign keys identified
• One approach to database has 4 stages:
1. Identify all entities
2. Identify all relationships between entities
3. Identify all attributes
4. Resolve all relationships
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Database Design (continued)
• The first three stages are performed by, for example,
interviewing staff (managers and users), observing staff at
work and reviewing existing documentation
• Relationships between entities are governed by
enterprise (or ‘business’) rules
• Resolving a relationship means deciding how to
implement it – which primary key will be used as a foreign
key, or whether to use a linking table (see Figure 5.5)
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Creating and modifying the database
• Data definition language (DDL):
collection of instructions and commands
used to define and describe data and
relationships in a specific database
– Allows the database’s creator to describe the
data and relationships that are to be contained
in the schema
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
SQL to define a table
CREATE DATABASE Lettings;
USE Lettings;
CREATE TABLE landlords(
Firstname CHAR(10),
Surname CHAR(10),
Telephone CHAR(10));
INSERT INTO landlords(
‘John’, ‘Smith’, ‘123456’);
Figure 5.7 SQL as a DDL
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Data dictionary
• Stores meta data, a detailed description of
all the data used in the database, to achieve
the following:
– Reduced data redundancy
– Increased data reliability
– Assists program development
– Easier modification of data and information
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
SQL to manipulate data
• The commands that are used to manipulate the database
are a data manipulation language (DML)
SELECT * FROM EMPLOYEE
WHERE JOB_CLASSIFICATION = “C2”.
• This will output all employees who have a job
classification of ‘C2’
• The * tells the DBMS to include all columns from the
EMPLOYEE table in the results
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Database Output
• After a database has been set up and loaded with data, it can produce
any desired reports, documents
• These outputs usually appear in screen displays or hard-copy
printouts
• The output-control features of a database program allow you to select
the records and fields to appear in reports
• You can also make calculations specifically for the report by
manipulating database fields
• Formatting controls and organisation options (such as report
headings) help you to customise reports and create flexible,
convenient, and powerful information-handling tools
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Database Management System (DBMS)
• Creating and implementing the right
database system ensures that the database
will support both business activities and
goals
• DBMS: a group of programs used as an
interface between a database and
application programs or a database and the
user
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Selecting a DBMS
• Important characteristics of databases to
consider:
– Database size
– Database cost
– Concurrent users
– Performance
– Integration
– Vendor
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Database Administration
• Role of the database administrator (DBA) is to plan,
design, create, operate, secure, monitor and maintain
databases
• The DBA works with both users and programmers
• A data administrator is responsible for defining and
implementing consistent principles for a variety of data
issues, including setting data standards and data
definitions; a nontechnical position
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Database Applications
• Today’s database applications manipulate
the content of a database to produce useful
information
• Common manipulations are searching,
filtering, synthesizing and assimilating the
data contained in a database using a
number of database applications
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Linking Databases to the Internet
• Linking databases to the Internet is
important for many organizations and
people
• Semantic Web
– Developing a seamless integration of traditional
databases with the Internet
– Allows people to access and manipulate a number of
traditional databases at the same time through the
Internet
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Data Warehouses & Data Mining
• Data warehouse: database that collects
business information from many sources in
the enterprise, covering all aspects of the
company’s processes, products and
customers
• Data mining: information-analysis tool that
involves the automated discovery of
patterns and relationships in a data
warehouse
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Data mining
• Data mining is the process of analysing data to try to discover
patterns and relationships within the data
• Typically, a data warehouse is mined
• Like gold mining, data mining sifts through mountains of data to
find a few nuggets of valuable information
• There are a number of data mining tools and techniques
• Association rules algorithms are used to find associations
between items in the data. For example, if someone buys eggs,
how likely is it that they will also buy cheese?
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Data mining (continued)
• Data mining is used extensively in marketing
to improve customer retention; identify crossselling opportunities; manage marketing
campaigns; market, channel and pricing
analysis; and customer segmentation analysis
(especially one-to-one marketing)
• Data-mining tools help users find answers to
questions they haven’t thought to ask
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Business Intelligence
• Business intelligence (BI): process of
gathering enough of the right information
in a timely manner and usable form and
analyzing it to have a positive impact on
business strategy, tactics, or operations
• Turns data into useful information that is
then distributed throughout an enterprise
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Distributed databases
• Distributed database
– Database in which the data may be spread
across several smaller databases connected via
telecommunications devices
– Gives corporations more flexibility in how
databases are organized and used
• Replicated database
– Database that holds a duplicate set of
frequently used data
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Online Analytical Processing (OLAP)
• Software that allows users to explore data
from a number of different perspectives
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Visual, Audio, and Other Database Systems
• Databases for storing images
• Databases for storing sound
• Virtual database systems: allow different
databases to work together as a unified
database system
• Other special-purpose database systems
– Spatial data technology: stores and accesses data
according to the locations it describes and permits
spatial queries and analysis
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Object-Oriented and Object-Relational DBMS
• Object-oriented database: database that stores both data
and its processing instructions
– Method: procedure or action
– Message: request to execute or run a method
• Object-oriented database management system
(OODBMS): group of programs that manipulate an objectoriented database and provide a user interface and
connections to other application programs
• Object-relational database management system
(ORDBMS): DBMS capable of manipulating audio, video,
and graphical data
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Summary
• Relational Database: a collection of tables used
to store data
• Primary Key: a field or set of fields in a record
that is used to identify the record
• Database approach to data management: a pool
of related data is shared by multiple application
programs
• Database design: list of tables with primary and
foreign keys identified
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Summary (continued)
• Database management system (DBMS):
group of programs used as an interface
between a database and application
programs or a database and the user
• Role of the database administrator (DBA):
plan, design, create, operate, secure,
monitor and maintain databases
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning
Summary (continued)
• Data warehouse: database that collects business
information from all aspects of a company’s processes,
products, and customers
• Data mining: information-analysis tool for the automated
discovery of patterns and relationships in a data
warehouse
• Object-oriented database: database that stores both data
and its processing instructions
For use with Fundamentals of Business Information Systems 2e
By Ralph Stair, George Reynolds and Thomas Chesney
1408044218 © 2012 Cengage Learning