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Networked Database
Applications
and Reengineering
Copyright 1996 Prentice-Hall
2
Client/Server Database
Client Database Program
Server Database Program
(Excel)
(Oracle)
Application Request Message
Application Response Message
Platform Independent
Thanks to TCP
Client, server can be
any type of machine
Network or Internet
3
Access to Multiple Databases
Database Program X
Server 1
Integrated
Report
Client
Program
Database Program Z
Server 4
Database Program W
Server 6
4
Incremental Database Development
1
Data Entry Program
2
Credit Checking Program
3
Management Statistics
Program
4
Etc.
Server
Database
Program
5
ODBC: An Application Layer Protocol
Open Database Connectivity (Microsoft standard)
 Microsoft now pushing OLE

Client Program
(Application)
ODBC
Server Database Program
(Application)
Transport Layer
Transport Layer
Internet Layer
Internet Layer
Subnet Layer
Subnet Layer
Client Machine
Server Machine
6
Database Middleware

Problem: Incompatible database applications
– New systems that follow different standards
– Old (Legacy) systems that must be maintained
 One
solution
– Database middleware
– Layer below application layer
– Handles lower-layer details for application program
7
Database Middleware
Incompatible
Server
Program
Database
Middleware
Program
Transport
Internet
Subnet
Incompatible
Legacy
Program
Client
Program
Request
Response
Database
Middleware
Program
File
Transfer
Transport
Internet
Subnet
Physical Layer Connection
Database
Middleware
Program
Transport
Internet
Subnet
8
Data Warehouse

Problem: Users need data from multiple databases
– They need to integrate these data
– Different databases have different access methods
– Queries to operational databases would cause
performance problems for operational use
– Queries to operational databases could cause security
problems
9
Data Warehouse
 Solution
– Extract data to a “data warehouse”
– Clean up the data
– Give users access and analysis tools
Inventory
Database
Client
Program
Sales
Database
Data
Warehouse
Planning
Database
10
Data Warehouse Tools

Multidimensional databases
– Can search easily by region, product, salesperson, etc.

Online Analytical Processing (OLAP)
– Special tools for analyzing data from databases
– Forecasts, etc.

Data Marts
– Limited data warehouses for departments, other groups
– Much easier to set up, rapid payback
11
Data Marts

Large data warehouses are difficult to create
and manage

Data marts offer similar services for smaller
groups, such as departments

Simpler, easier to develop
12
Fat Client
Tiers

Two-Tier Processing
Database
Server
– Server handles database access
– Client handles user interface
– Client may have to handle extensive calculation based
on business rules. (“Extend credit if the following 20
conditions are met.)
– Business rules processing can result in “fat clients”
with the power normally required for servers
13
Three-Tier Processing

Client only handles user interface: Thin client

Business rules server handles complex
calculations
 Database
server: Retrieves appropriate data
Thin
Client
Database
Server
Business Rules Server
14
On the World Wide Web

Client fills out form in browser program on PC
– Passes form to webserver
Browser
Webserver
Form
15
On the World Wide Web

Webserver receives the form
– Passes request to a database access program
Browser
Webserver
Database
Access Program
16
On the World Wide Web

Database access program formulates request
– Sends to database program
Database
Access Program
Database
Program
17
On the World Wide Web

Database program retrieves data
– Passes to the database access program
Database
Access Program
Database
Program
18
On the World Wide Web

Database Access Program Puts Answer in Webpage
– Passes page to the server, which passes it to browser
Browser
Webserver
Database
Access Program
19
On the World Wide Web

Interactions between the webserver and the database must
be standardized

CGI
– Common Gateway Interface is the oldest standard
– Standardizes ways of passing data values to DBMS
– Standardizes ways of receiving results from DBMS,
sending as webpages
– Slow: each interaction restarts the DBMS program,
unless proprietary APIs are used
20
On the World Wide Web

Interactions between the webserver and the database must
be standardized

APIs
– Application Program Interface
– Standardized way for any application program,
including webservers, to send calls to DBMSs, get
responses
– High-performance
– Different DBMSs have different APIs
– Most webservers support only some DBMS APIs
21
Distributed Databases
Form 1
Replicate
Update
Replicate
Form 2
Update
22
Distributed Databases

Store data near users for rapid response

Safety in case of a site disaster

Replication
– Propagating changes to appropriate databases
– Often must be done in real time
– Otherwise, two travel agents would sell the same
airline seat
23
Multimedia Databases

Graphics, sound, even video
Telephone Directory
Last name:
Lee
First name:
Pat
Extension:
x6894
Click to hear Pat’s
Recorded Greeting
Pat’s
photo
will go
here.
24
Commercial Online Services
Provide For-Fee Information
 Usually Internet access too
(new)

User
PC &
Modem
WAN
Internal Services:
Information
Communication
Processing
Commercial
Online
Service
The Internet
25
Commercial Online Services

Consumer-Oriented Services
– Focus on residential users
– Widely touted in the media
– America Online, CompuServe, Microsoft Network
– Small part of online services business
– Internet makes their future uncertain
26
Commercial Online Services

Business Processing Services
– Payroll
– Insurance claims clearing houses, etc.
– Very large

Business Information Services
– Credit checking, etc.
– Corporate financial information
– Very large
27
Commercial Online Services

Electronic Data Interchange (EDI)
– Business exchange high-volume business documents
– Invoices
– Orders, etc.
– Still rather small

Electronic Funds Transfer (EFT)
– Send money electronically
– Very large intra-bank systems
28
Reengineering

If you simply automate what you are doing now,
gains will be very small

To get large gains
– Find a more efficient way to do the end goal
– You need a new strategy
– Use information technology (if needed) to get you there
– Good implementation is critical
29
Reengineering

Importance of IT
– Removes old limitations that forced us to work certain
ways
– But only those who can grasp new possible strategies
will benefit
30
Obliterate Work

Work is caused by business rules
– Suppliers must furnish us with invoices

Drop rules if they no longer make sense
–
–
–
–
–
–
Ford Motor Company
Suppliers now delivery goods without invoices
Ford reads the Universal Product Code on boxes
Ford pays automatically
Slashed accounts payable department
The best way to massive gains
31
Consolidate Work

Bad for work to send job from one department to
another in sequence
– In each department, waits in line for processing
– Long delays in processing
– High cost because many people are involved

Why send work between departments?
– Before, each department had needed information in its
paper files and in the heads of people
32
Consolidate Work

Today
– Any employee can get data from distant databases
– No need to ship work between departments
 Case
worker
– Does whole task previously done by many
– Like airlines reservations clerk

Case teams
– Where individual workers cannot do the job alone
33
Teams

Form teams only as needed

Get right mix of people for the job

Disband the team afterward

Companies may consist mostly of such teams
– Ad hocracies
 Virtual
corporations
– Membership may include people outside the firm
34
Interorganizational Systems

Vertical Cooperation
– Manufacturer, wholesalers, or retailers may cooperate
– Traditionally called the marketing system
– Supplier sends goods just in time by reading buyer’s
internal database system
– Creates new relationships: partnerships
35
Interorganizational Systems

Horizontal Cooperation
– Firms that are competitors band together to offer a
service
– Banking ATM networks
– Again, new relationships

Difficult because of natural competitiveness
36
Outsourcing

Decide on a firm’s core business processes
– Provide firm’s sustainable competitive advantage

Outsource other (non-core) business processes to
another firm
– Manage on a contractual basis

Outsourcing firms should be less expensive
– Specialization should bring economies of scale
37
New Channels

Internet allows us to reach world-wide audiences
– Very large audiences for massive sales
– Specialized audiences reached no other way
 The
Internet
– Sell less expensively
– Provide more data to customers
– Route customer questions to experts
– Eliminate the cost and stocking time required for
traditional retailing
38
Telecommuting

Spending some or all of the workday away from
the office

Reduces commuting time and road congestion
 Can
provide satisfaction to telecommuters,
enhancing retention

But managers spend 85% of the day
communicating, 55% face-to-face.
– Will coordination be harmed?

How can teleworkers be managed, assessed?