Review of Information Systems Introduction

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Review of Information Systems Introduction

• Information systems describe processes that
  transform data into information, using digital
  technology, to enable organizations to make
  better decisions
• requires inputs, outputs, processes, feedback
• composed of hardware, software, databases,
  infrastructure, people and procedures
• classified into transaction processing systems,
  e-commerce, management information systems and
  decision support systems
• Computer hardware encompasses all digital
  machinery used to input, store, process and
  output data
• CPU memory is computers heart, linked to
  input devices, output devices, communications
  devices, secondary storage
• Computer systems include network computers, PCs,
  workstations, midrange computers, mainframes and
  supercomputers

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Information Systems Introduction (contd)

• Computer software encompasses all programs that
  direct hardware to perform specific tasks
• types include operating system, utility,
  application software
• application software purchase options include
  proprietary, off-the-shelf and customized
• application software scope includes personal,
  workgroup and enterprise
• applications are developed using languages
• software cost dominates organization IS total
  costs
• The Internet is a worldwide linkage of computers
  that communicate
• Every host sends, receives and transfers messages
  and has a unique URL
• Internet services include e-mail, FTP/telnet,
  Usenet and telephony
• The World Wide Web allows organized access to
  documents anywhere on the Internet

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Why Do We Focus on Relational Databases?

• Databases are the lifeblood of any organization
  and answer the who/what/when/where/why of
  operations.
• Relational databases store large volumes of data
  with a minimum of data duplication,
  inconsistency, or anomalies, and encode key
  business practices
• Relational database management systems address
  the collection, storage and management of data in
  a relational databases, using
• Tables
• Queries
• User interfaces
• Reports
• Application programs

Growth in Internet communications has increased
the importance of relational database design and
applications
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Heinz School Network Information

• Computer information
• Nearly 100 computers in the clusters, nearly all
  running Windows NT one Mac.
• Nearly 100 more computers given to staff,
  faculty, Ph.D students, etc. Staff and faculty
  machines generally run Windows 95 Ph.D student
  machines run Windows NT
• Server information
• Five servers Sparc and NT servers for websites,
  three-server setup for our Heinz domain
  controllers (one primary, two backups). A few
  stand-alone servers as well.
• All servers will eventually run on Windows NT
  Server.
• Novell vs. NT
• Novell considered more robust, more stable and
  less able to be hacked than Windows NT
• Corporate purchasing decisions are dominating
  technical considerations

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The Wide World of Heinz

• The computing world at Heinz is divided into two
  
• The web server (domain www.heinz.cmu.edu) called
  Howland a Sun Solaris machine running Unix
• Howland is connected to the Andrew file system
• the PC world (domain HEINZ), in which three NT
  servers connect all faculty, staff and student
  computers, web/database/Exchange servers
• HEINZ domain is part of the CMU meta-domain

CMU meta-domain
NT
Unix
http//www.andrew.cmu.edu
NT Server 1
http//www.heinz.cmu.edu
AFS
NT Server 3
NT Server 2
Communicate via FTP
Howland (Heinz School webserver)
Faculty, student, staff, servers
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Overview of the Relational Database Model

• Relational databases can store any type of data
• IDs
• Codes
• Memos
• Numerical Values
• Hypertext Links
• Images/Sounds
• Date/Time
• Spatial attributes
• OLE

All organizations use these types of data in
their operations, but fewer use databases to
define relationships between data
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Relational Database Example Service Delivery

• Aardvark Towing , Inc.
• Mission Tow vehicles from pick up sites to
  destinations, charging by the mile towed.
• Resources 5 trucks, 20 drivers, radio dispatch,
  police scanners
• Problems Need to automate records, beat out the
  competition
• Solution Database, change from random to
  targeted truck locations

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First Step in Relational Database Design
Identify Entity Sets
Entity Set Collection of similar persons,
things, places, events, concepts, or linkages

• Potential Entity Sets
• TRUCK
• DRIVER
• VEHICLE
• TOW
• VEHICLE DRIVER

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Second Step Identify Primary Keys for Entity
Sets

• Primary Key Has a unique value for every entity
• Candidate Key Alternate primary key

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Third Step Identify Attributes of Entity Sets
Attribute Characteristic or property of entities
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Data Example tblTruck
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Next Step Design Entity-Relationship Diagram

• An entity-relationship (E-R) diagram is a
  blueprint of the relational database. It defines
  associations between and within entities that
  capture connectivity, cardinality, functional
  relationship and others.

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Relationships Between Tables - Example
tblTruck
tblTow
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Last Step Full Relational Database Model

• tblTruck (Truck, Truck VIN, Truck Plate,
• Truck Make And Model Code, Truck
  Year)
• tblEmployee (Employee, Social Security Number,
  First Name,
• Last Name, Address,
  Phone, DOB)
• tblVehicle (Vehicle VIN, Driver_at_, Vehicle
  Plate,
• Vehicle State, Vehicle Make
  and Model Code,
• Vehicle Type, Vehicle Year,
  Insurance Co.)
• tblTow (Tow, Truck_at_, Employee_at_, Vehicle VIN_at_,
  Date Towed,
• Time Towed, Pick Up Address, Pick
  Up Zone,
• Destination Address, Distance Towed
  (Miles), Comment)
• tblVehicleDriver (Driver, First Name, Last Name,
  Operator,
• Street Address,
  City, Zip Code, State,
• Phone, Owner? )

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What Else Is Needed to Create a RDBMS for
Aardvark Towing, Inc.?

• Build case for relational database management
  system
• Learn business rules, data sources
• Define and populate tables using a relational
  database software
• Implement E-R diagram relationships
• Build forms for data entry
• Display spatial data in GIS
• Implement spatial and aspatial queries
• Design summary reports
• Implementation and testing