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Chapter 3
Data
and
Knowledge
Management
www.pearsoned.ca/jessup
Robert Riordan, Carleton University
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Learning Objectives
1. Describe why databases
have become so important
to organizations
2. Describe what databases
and database management
systems are and how they
work
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Learning Objectives
3. Explain how organizations
are getting the most from
their investment in database
technologies
4. Describe what is meant by
knowledge management and
knowledge assets as well as
benefits and challenges of
deploying a knowledge
management system
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Database Technology
• A collection of related data organized in
a way that makes it valuable and useful
• Allows organizations to retrieve, store,
and analyze information easily
• Is vital to an organization’s success in
running operations and making
decisions
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Database Terminology
Entities
• Things we store information about. (i.e.
persons, places, objects, events, etc.)
• Have relationships to other entities (i.e. the
entity Student has a relationship to the entity
Grades in a University Student database
Attributes
• These are pieces of information about an
entity (i.e. Student ID, Name, etc. for the
entity Student)
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Relationship of DBMS Concepts to Others?
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Levels of a Database Management System (DBMS)
Level
Term
Term Definitions
Lowest
Highest
Field
Individual characteristics about an ENTITY.
Fields are also called attributes or columns
depending on the type of DBMS
Record
A group of fields or attributes to describe a
single instance of an ENTITY. These are
also called rows depending on the DBMS
File
A collection of records or instances for a
given ENTITY. These are also called tables,
depending on the DBMS
Database
A collection of files or entities containing
information to support a given system or a
particular topic area
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View of a Database Table or File
Attribute
(One Column)
Attribute
Type
Record
(One
Row)
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File Processing vs. Database Approach Summary
File Processing Approach (Old School)
• Storage Media: sequential tapes or files
• Data: stored in long sequential files
• Organization: redundant data in multiple files
• Efficiency: data embedded to support processing
• Updates: requires multiple updates in many files
• Processing: slower query/faster processing
Data Base Approach (New School-TODAY)
• Storage Media: Direct Access Storage Device (DASD)
• Data: stored in related tables
• Organization: redundant data minimized/eliminated
• Efficiency: data stored only in tables
• Updates: requires few or one update for a data field
• Processing: faster query/slower processing
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Advantages of the Database Approach
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Costs or Risks of the Database Approach
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Database Systems Activities – Data Entry
Employment
Applications
Enter
Forms
(Form Entry Screen)
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Example
• Data is entered from paper employment
applications into a form entry screen
• The entry forms are designed to match
the paper forms for ease of entry
• The form data is processed by the entry
program and then stored in the
employment database
(Form Entry Program)
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(Employment DB)
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Database Systems Activities – Query
Query – A database function that extracts and displays information
from a database given selection parameters.
SQL (Structured Query Language)
• A language to select and extract data from a database
• The industry standard language for relational databases
QBE (Query by Example)
• A technique that allows a user to design a query on a screen by
dragging and placing the query field in their desired locations
Example – Display applicants entered in the last 30 days
• Query parameters are selected in the query request screen
• The database program uses SQL to query and present the result
(Query Request)
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(Query Program)
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(Employment Query)
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Database Systems Activities – Report
Report – A database function that extracts and formats information
from a database for printing and presentation
Report Generator
• A specialized program that uses SQL to retrieve and manipulate
data (aggregate, transform, or group)
• Reports are designed using standard templates or can be custom
generated to meet informational needs
Example – Report on applicants entered in the last 30 days
• Report parameters are selected in the report request screen
• The database program uses SQL to query and present the result
(Query Request)
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(Query Program)
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(Employment Report)
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Designing Databases – Data Model
Data Model
• A map or diagram that represents entities and
their relationships
• Used by Database Administrators to design tables
with their corresponding associations
Example: ERD (Entity Relationship Diagram)
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Designing Databases – Keys
Database Keys
Mechanisms used to identify, select, and maintain one or
more records using an application program, query, or report
Primary Key
A unique attribute type used to identify
a single instance of an entity
Compound Primary Key
A unique combination of attribute types used to
identify a single instance of an entity
Secondary Key
An attribute that can be used to identify one or more records
within a table with a given value
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Designing Databases – Keys (Example)
Primary
Key
ENTITIES
- Student ID
Entities are translated
into Tables
(Students and Grades)
Secondary
Key
- Major
Entities are
joined by
common
attributes
Compound
Primary Key
- Student ID
- Course ID
- Sec No.
- Term
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Designing Databases - Associations
Associations
• Define the relationships one entity has to another
• Determine necessary key structures to access data
• Come in three relationship types:
- One-to-One
- One-to-Many
- Many-to-Many
Foreign Key
• An attribute that appears as a non-primary
key in one entity (table) and as a primary key
attribute in another entity (table)
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Designing Databases - Associations
Entity Relationship Diagram (ERD)
• Diagramming tool used to express entity relationships
• Very useful in developing complex databases
Example
• Each Home Stadium has a Team (One-to-One)
• Each Team has Players (One-to-Many)
• Each Team participates in Games
• For each Player and Game there are Game Statistics
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Designing Databases - Associations
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Designing Databases – Associations (Example)
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The Relational Model
The Relational Model
• The most common type of database model used
today in organizations
• Is a three-dimensional model compared to the
traditional two-dimensional database models
- Rows (first-dimension)
- Columns (second-dimension)
- Relationships (third-dimension)
• The third-dimension makes this model so powerful
because any row of data can be related to any
other row or rows of data
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The Relational Model - Example
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The Relational Model - Normalization
Normalization
• A technique to make complex databases more efficient by
eliminating as much redundant data as possible
• Example: Database with redundant data (below)
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The Relational Model - Normalization
Normalized Database
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The Relational Model – Data Dictionary
Data Dictionary
• Is a document that database designers prepare to help
individuals enter data
• Provides several pieces of information about each
attribute in the database including:
- Name
- Key (is it a key or part of a key?)
- Data Type (date, alphanumeric, numeric, etc.)
- Valid Value (the format or numbers allowed)
• Can be used to enforce Business Rules which are
captured by the database designer to prevent illegal or
illogical values from entering the database. (e.g. who has
authority to enter certain kinds of data)
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Online Transactional Processing (OLTP)
Online Transactional Processing
• The mechanism by which customers, suppliers, and
employees process business transactions for an organization
• These users conduct transactions online through internal
systems and external websites for processing and storage
Example
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Operational vs. Informational Systems
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Organizational Use of Databases
Operational
Informational
Extract
Data
Extract
Data
Department
Databases
Data
Warehouse
• Day-to-day
department
transactions
• Used primarily by
departments
• Extracted
department
transactions
• Used for
business
analysis
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Data
Mart
• Extracted
subset of a data
warehouse
• Used for highly
specific business
analysis
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DATA WAREHOUSES, DATA MARTS, DATA MINING
• Data _______ : collects business information from many
sources in the enterprise
• Data _______ : a subset of a data warehouse
• Data _______ : an information-analysis tool for
automated discovery of patterns and relationships in a
data warehouse or a data mart
• Online ______________ Processing -Graphical
software tools that provide complex analysis of data
stored in a database
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DATA WAREHOUSES, DATA MARTS, DATA MINING
• Data _______ are not
transaction-oriented.
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• Data _______ support
online analytical
processing (OLAP).
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Online Analytical Processing (OLAP)
Online Analytical Processing
• Graphical software tools that provide complex analysis
of data stored in a database
• OLAP tools enable users to analyze different
dimensions of data beyond summary and simple
aggregations of normal database queries
• The OLAP Server is the chief component of an OLAP
system which understands how the data is organized and
has special functions for analyzing data
• OLAP can provide time series and trend analysis views
of data, data drill-downs, and the ability to answer
“what-if” and “why” questions as part of its function
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Data Mining
Data Mining
• Is a method companies use to analyze information to
better understand their customers, products, markets, or
any other phase of the business for which they have data
• With data mining tools you can graphically drill down,
sort or extract data based on certain conditions;
perform a variety of statistical analysis
• Data mining applications are very powerful and use highly
complex algorithms to analyze and to identify
opportunities
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Data Warehouse Example
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Uses of Data Warehousing
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Knowledge Management Definitions
Knowledge Management
The process an organization uses to gain the greatest value
from its knowledge assets
Knowledge Assets
All underlying skills routines, practices, principles, formulae,
methods, heuristics, and intuitions whether explicit or tacit
Explicit Knowledge
Anything that can be documented, archived, or codified
often with the help of information systems
Tacit Knowledge
The processes and procedures on how to effectively
perform a particular task stored in a person’s mind
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Knowledge Management System (KMS)
Best Practices
Procedures and processes that are widely accepted as
being among the most effective and/or efficient
Primary Objective
How to recognize, generate, store, share, manage this tacit
knowledge (Best Practices) for deployment and use
Technology
Generally not a single technology but rather a collection
of tools that include communication technologies (e.g.
e-mail, groupware, instant messaging), and information
storage and retrieval systems (e.g. database
management system) to meet the Primary Objective
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Benefits and Challenges of Knowledge Management
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Roles in Database Development and Use
Database Administrator (DBA)
• Designs, develops and monitors
performance of databases
• Enforces policy and standards
for data use and security
Systems Programmer
• Creates business applications
that connect to databases
• Tests the new systems and
databases before use
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Systems Analyst
• Defines data requirements
working with a DBA
• Incorporates the database
design into new program
designs
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