3-1 Chapter 3 Data and Knowledge Management Robert Riordan, Carleton University.

3-1

Chapter 3

Data and

KnowledgeManagement

www.pearsoned.ca/jessup

Robert Riordan, Carleton University

3-2Information Systems Today, 2/C/e ©2008 Pearson Education Canada

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


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


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


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)


Relationship of DBMS Concepts to Others?


Levels of a Database Management System (DBMS)

Database

Record

File

FieldIndividual characteristics about an ENTITY. Fields are also called attributes or columns depending on the type of DBMS

Term

A group of fields or attributes to describe a single instance of an ENTITY. These are also called rows depending on the DBMS

A collection of records or instances for a given ENTITY. These are also called tables, depending on the DBMS

A collection of files or entities containing information to support a given system or a particular topic area

Term DefinitionsLowest

Highest

Level


View of a Database Table or File

Attribute(One Column)

Record(One Row)

AttributeType


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


Advantages of the Database Approach


Costs or Risks of the Database Approach


Database Systems Activities – Data Entry

EnterForms

Employment Applications

(Form Entry Screen) (Form Entry Program) (Employment DB)

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


Database Systems Activities – Query

(Query Request) (Query Program) (Employment Query)

SQL (Structured Query Language)• A language to select and extract data from a database • The industry standard language for relational databasesQBE (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

Query – A database function that extracts and displays information from a database given selection parameters.

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


Database Systems Activities – Report

(Query Request) (Query Program) (Employment Report)

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

Report – A database function that extracts and formats information from a database for printing and presentation

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


Designing Databases – Data Model

Example: ERD (Entity Relationship Diagram)

Data Model• A map or diagram that represents entities and

their relationships• Used by Database Administrators to design tables

with their corresponding associations


Designing Databases – Keys

Primary KeyA unique attribute type used to identify a single instance of an entity

Secondary KeyAn attribute that can be used to identify one or more records within a table with a given value

Compound Primary KeyA unique combination of attribute types used to identify a single instance of an entity

Database KeysMechanisms used to identify, select, and maintain one or more records using an application program, query, or report


Designing Databases – Keys (Example)

Primary Key- Student ID

ENTITIES

Compound Primary Key- Student ID - Course ID - Sec No.- Term

SecondaryKey- Major

Entities are translated into Tables

(Students and Grades)

Entities arejoined by commonattributes


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)



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




Designing Databases – Associations (Example)


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


The Relational Model - Example


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)


The Relational Model - Normalization

Normalized Database


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)

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)


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


Operational vs. Informational Systems


Organizational Use of Databases

DepartmentDatabases

Data Warehouse

Data Mart

Operational Informational

ExtractData

ExtractData

ExtractData

ExtractData

•Day-to-day department transactions

•Used primarily by departments

• Extracted department transactions

• Used for business analysis

• Extracted subset of a data warehouse

• Used for highly specific business analysis

3-31Information Systems Today, 2/C/e ©2008 Pearson Education Canada31

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


32

• Data _______ are not transaction-oriented.

• Data _______ support online analytical processing (OLAP).

DATA WAREHOUSES, DATA MARTS, DATA MINING


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


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


Data Warehouse Example


Uses of Data Warehousing


Knowledge Management Definitions

Knowledge AssetsAll underlying skills routines, practices, principles, formulae, methods, heuristics, and intuitions whether explicit or tacit

Tacit KnowledgeThe processes and procedures on how to effectively perform a particular task stored in a person’s mind

Explicit KnowledgeAnything that can be documented, archived, or codified often with the help of information systems

Knowledge ManagementThe process an organization uses to gain the greatest value from its knowledge assets


Knowledge Management System (KMS)

Primary ObjectiveHow to recognize, generate, store, share, manage this tacit knowledge (Best Practices) for deployment and use

TechnologyGenerally 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

Best PracticesProcedures and processes that are widely accepted as being among the most effective and/or efficient


Benefits and Challenges of Knowledge Management


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

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

Systems Programmer• Creates business applications

that connect to databases• Tests the new systems and

databases before use

Systems Analyst• Defines data requirements

working with a DBA • Incorporates the database

design into new program designs

Systems Analyst• Defines data requirements

working with a DBA • Incorporates the database

design into new program designs

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3-1 Chapter 3 Data and Knowledge Management Robert Riordan, Carleton University.

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