Data

1
Chapter 3 Data and Knowledge Management www.p
renhall.com/jessup
2
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

3
Learning Objectives

• Explain how organizations are getting the most
  from their investment in database technologies
• Describe what is meant by knowledge management
  and knowledge assets as well as benefits and
  challenges of deploying a knowledge management
  system

4
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 organizations success in running
  operations and making decisions

5
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)

6
Relationship of DBMS Concepts to Others?
7
Levels of a Database Management System (DBMS)
Term
Term Definitions
Level
Lowest
Individual characteristics about an ENTITY.
Fields are also called attributes or columns
depending on the type of DBMS
Field
A group of fields or attributes to describe a
single instance of an ENTITY. These are also
called rows depending on the DBMS
Record
A collection of records or instances for a given
ENTITY. These are also called tables depending on
the DBMS
File
A collection of files or entities containing
information to support a given system or a
particular topic area
Database
Highest
8
View of a Database Table or File
Attribute (One Column)
Attribute Type
Record (One Row)
9
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 only stored only in tables
• Updates requires few or one update for a data
  field
• Processing faster query/slower processing

10
Advantages of the Database Approach
11
Costs or Risks of the Database Approach
12
Roles in Database Development and Use

• Database Administrator (DBA)
• Designs, develops and monitors performance of
  databases
• Enforces policy and standards for data uses and
  security

• Systems Analyst
• Defines data requirements working with a DBA
• Incorporates the database design into new program
  designs

• Systems Programmer
• Creates business applications that connect to
  databases
• Tests the new systems and databases before use

13
Database Systems Activities Data Entry
Employment Applications

• Example
• Data is entered from paper employment
  applications into a form entry screen
• The entry forms are designed to match the paper
  forms for easy entry
• The form data is processed by the entry program
  and then stored in the employment database

Enter Forms
(Form Entry Screen)
(Form Entry Program)
(Employment DB)
14
Database Systems Activities Query
Query A database function that extracts and
displays information from a database given
selection parameters.

• SQL (Structure 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)
(Query Program)
(Employment Query)
15
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)
(Query Program)
(Employment Report)
16
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)
17
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
attributes 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
18
Designing Databases Keys (Example)
ENTITIES
Primary Key - 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
19
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)

20
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

21
Designing Databases - Associations
22
Designing Databases Associations (Example)
23
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

24
The Relational Model - Example
25
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)

26
The Relational Model - Normalization
Normalized Database
27
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, alpha-numeric, 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)

28
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
29
Operational vs Informational Systems
30
Organizational Use of Databases
Operational
Informational
Extract Data
Extract Data
Data Mart
Department Databases
Data Warehouse

• 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

31
Online Analytical Processing (OLAP)

• Online Analytical Processing
• Graphical software tools that provide complex
  analysis of data stored on a database
• OLAP tools enable users to analyze different
  dimensions of data beyond data summary and data
  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 functions

32
Data Mining

• Data Mining
• Is a method companies use to analyze information
  to better understand their customers, products,
  markets, or any other phase of their 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

33
Data Warehouse Example
34
Uses of Data Warehousing
35
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, formulas, 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 persons mind
36
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
instead 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
37
Benefits and Challenges of Knowledge Management