Transcript Data - U of L Personal Web Sites

Data
Information Systems and
Management
Valuing Organizational
Information
• Transactional Information
– Contained within a business process
– Supports performing daily operations
• Analytical Information
– Includes transactional information plus market and
industry information
• The Value of Timely Information
– Real Time: Immediate, up-to-date
– Within the Decision Makers Time frame
Characteristics of HighQuality Information
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Accuracy
Completeness
Consistency
Uniqueness
Timeliness
The Cost of Low-Quality
Information
• Using the wrong information can
lead to making the wrong
decision
• The wrong decision can cost
time, money, and even
reputations
The Benefits Of High-Quality
Information
• Improve chances of making a
good decision which, in turn,
may directly affect the
organization’s bottom line
Data Resource Management
Data Planning
• Develop an overall data and architecture
for the firm’s data resources that ties in
with the firm’s strategic mission and plans,
and the objectives and processes of it’s
business units.
Data Administration
• Involves the establishment and
enforcement of policies and procedures
for managing data as a strategic corporate
resource.
Database Structures
• Hierarchical
• One-to-many (Tree like)
• Network
– Many-to-many
• Relational
– Elements reside in two dimensional interlinked tables
• Multidimensional
– Cubes of data
• Object Oriented
– Encapsulation: data and operations are stored together
Entity Relationship Diagram
(ERD)
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Tool Used In Data Modeling
Depicts relationships between entities
Entity: a category of stored data
Relationship: how entities are associated
Attributes: descriptive components of an
entity
• An ERD model can be easily translated
into virtually any type of physical data
base implementation
Entity Relationship Diagram
Customer
Order
Item
Rules Of Thumb
• 1:1 : One Table
• 1:M :primary key from one side used as a
foreign key in the many side
• M:M : New table with a primary key which
is a combination of both the other primary
keys.
Rules Of Thumb
Bit
Byte ≡ Character
Field
≡
Record
≡
File
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Data Element ≡
Data Structure
Database
Primary Key
Secondary Key (or Foreign Key)
Referential Integrity
Normalization
Attributes
Entity
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≡ Table
Relational
Database
Referential Integrity
The Primary key data must exist
before data can be entered in
the table where the primary key
is used as a Foreign key.
Normalization
• A method of simplifying complex data
structures
• A process of assigning attributes to
entities
• Determine how to traverse a relational
database by identifying primary keys and
foreign keys
Normalization
First Normal Form (1NF)
• An entity is in 1NF if there are no elements, or
group of elements, which repeat for a single
occurrence of the entity.
Second Normal Form (2NF)
• An entity is in 2NF if it is in 1NF and if the full
key and not part of it derive all non-key
elements
Third Normal Form (3NF)
• An entity is in 3NF if it is in 2NF and if the
values for the non-key elements are not
dependent on any other non-key elements.
ERD Example
Faculty
Course
Student
Department
U of L Database
Calendar
HR
Course
Faculty
•Course # (K)
•Course Name
•Course Description
•Faculty # (k)
•Fac. # (K)
•Name
•Address
•Dept # (k)
Phone
Book
Department
•Dept. # (K)
•Dept. Name
•Dept. Description
Organizational
Chart
Course #
Student #
Mark
Student
•Student # (K)
•Student Name
•Student Address
Registration
To Grading
System
Admissions
Organizing Data
• Data is processed into information which
in turn supports decision making
• Database Management System (DBMS)
– User/database interface
• Database Administrator (DBA)
– IT professional responsible for all aspects of the
database
Data Management
• For data to be turned into information it must first be
organized in a meaningful way
• Traditional approach
– Data redundancy: duplication of data in separate files
– Data integrity: the degree to which data is correct
• Database approach
– A pool of related data is shared by mulitple application
programs
Data Modeling
• Key Considerations:
• What data will be collected
• Who will have access to it
• How the data will be used
• Data Model
• A diagram of data entities and their
relationships
Data Modeling
• Enterprise Data Modeling
• Data modeling done at the enterprise level
• Entity Relationship Diagram (ERD)
• Use basic graphic symbols
• Show the organization and relationships
between data
• Planned Data Redundancy
• Summary totals carried in data
• To improve system performance
• Data Marts in ERP systems
The Relational Database Model
• Relational Model:
• A database model that describes data
in which all data elements are placed in
two dimensional tables
• The tables are the logical equivalent to
files
• Domain: Allowable values for data
attributes
Data Clean-up
• The process of looking for and
fixing inconsistencies to ensure
that data are accurate and
complete
Overview of Database Types
• Flat file
– Sequential or direct
– Does not use database concepts
• Single User
– One person can use the database at a time
(Access)
• Multiple Users
– Large DBMS (Oracle)
Providing a User View
• Schema:
• a description of the entire database
• Sub schema:
• a description of a subset of the
database
• Users can view and modify data terms
in the subset
Creating and Modifying the
Database
• Data Definition Language (DDL)
• Commands used to describe data and their
relationships
• Data Dictionary
• Detailed descriptions of all data in the
database
Storing and Retrieving Data
• The system must calculate the physical
location based upon logical application of
data
• Concurrency Control
• A method of dealing with two people
accessing the same location, in the
same database, at the same time
Manipulating Data and
Generating Reports
• Query-by-example (QBE)
– Point and click, drag and drop
• Data Manipulation Language (DML)
– Commands used to manipulate data in a database
– Structured Query Language (SQL)
Selecting a Database
Management System
• Determine information needs of the
organization
• Considerations
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Size (current and future)
Number of Concurrent Users
Performance (response time)
Integration (relation to other applications)
Features (security, privacy, templates)
The Vendor (service, reputation, viability)
Cost
Enterprise Resource Planning
• Replace functional mainframe legacy
systems with cross-functional client/server
network applications.
• SAP and others
Cross-Functional Information Systems
• Support business processes
• Production
• Distribution
• Order management
• Cross boundaries of Traditional business
functions.
• IT helps by supporting the re-engineering and
improvement of business processes.
• A strategic way to use IT to share information
resources and improve both efficiency and
effectiveness of business processes to help a
business attain it’s strategic objectives.
• Data Warehouse:
• A database that collects business
information from many sources in the
enterprise, covering all aspects of the
company’s processes, products, and
customers
• Data Mart:
• Subset of a data warehouse
Data Mining
• An information analysis tool that
involves the automated discovery of
patterns and relationships in a data
warehouse
• Predictive Analysis
• Combines historical data with
assumptions about future conditions
• Used to predict outcome of events
Business Intelligence
• The 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
• Competitive Intelligence
• Counter Intelligence
• Knowledge Management
More Business Intelligence
• Competitive Intelligence
– One aspect of business intelligence limited to
information about competitors
• Counter Intelligence
– The steps an organization takes to protect information
sought by “hostile” intelligence gathers
• Knowledge Management
– The process of capturing a company’s collective
expertise wherever it resides – in computers, on paper,
in people’s heads – and distributing it wherever it can
help produce bigger payoffs
Distributed Databases
• A database in which the data may spread
across several smaller databases
connected via telecommunication devices
• Replicated Database
– A database that holds a duplicate set of
data
Online Analytical Processing
(OLAP)
• Software that allows users
to explore data from a
number of different
perspectives
Object-Oriented
• Object-Oriented Database
• Database that stores both data and its
processing instructions together
• Encapsulation
Data
Information Systems and
Management