Networked Database Applicationsand Reengineering

Copyright 1996 Prentice-Hall

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Client/Server Database

Client Database Program(Excel)

Server Database Program(Oracle)

Application Request Message

Application Response Message

Network or Internet

Platform IndependentThanks to TCP

Client, server can beany type of machine

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Access to Multiple Databases

ClientProgram

ClientProgram

Database Program XServer 1

Database Program XServer 1

Database Program ZServer 4

Database Program ZServer 4

Database Program WServer 6

Database Program WServer 6

IntegratedReport

IntegratedReport

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Incremental Database Development

ServerDatabaseProgram

ServerDatabaseProgram

1Data Entry Program

1Data Entry Program

2Credit Checking Program

2Credit Checking Program

3Management Statistics

Program

3Management Statistics

Program

4Etc.

4Etc.

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ODBC: An Application Layer Protocol

Open Database Connectivity (Microsoft standard) Microsoft now pushing OLE

Client Program(Application)

Client Program(Application)

Transport LayerTransport Layer

Internet LayerInternet Layer

Subnet LayerSubnet Layer

Client Machine

Server Database Program(Application)

Server Database Program(Application)

Transport LayerTransport Layer

Internet LayerInternet Layer

Subnet LayerSubnet Layer

Server Machine

ODBC

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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

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Database Middleware

IncompatibleServer

Program

IncompatibleServer

Program

DatabaseMiddleware

Program

DatabaseMiddleware

Program

TransportInternetSubnet

TransportInternetSubnet

Physical Layer Connection

ClientProgram

ClientProgram

DatabaseMiddleware

Program

DatabaseMiddleware

Program

TransportInternetSubnet

TransportInternetSubnet

IncompatibleLegacy

Program

IncompatibleLegacy

Program

DatabaseMiddleware

Program

DatabaseMiddleware

Program

TransportInternetSubnet

TransportInternetSubnet

RequestResponse

FileTransfer

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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

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Data Warehouse Solution

– Extract data to a “data warehouse”– Clean up the data– Give users access and analysis tools

DataWarehouse

DataWarehouse

ClientProgram

ClientProgram

InventoryDatabase

InventoryDatabase

SalesDatabase

SalesDatabase

PlanningDatabase

PlanningDatabase

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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

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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

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Tiers

Two-Tier Processing

– 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

Fat Client

DatabaseServer

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Three-Tier Processing

Client only handles user interface: Thin client

Business rules server handles complex calculations

Database server: Retrieves appropriate data

ThinClient

DatabaseServer

Business Rules Server

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On the World Wide Web Client fills out form in browser program on PC

– Passes form to webserver

Form

Browser Webserver

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On the World Wide Web Webserver receives the form

– Passes request to a database access program

Browser WebserverDatabase

Access Program

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On the World Wide Web Database access program formulates request

– Sends to database program

DatabaseAccess Program

DatabaseProgram

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On the World Wide Web Database program retrieves data

– Passes to the database access program

DatabaseAccess Program

DatabaseProgram

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On the World Wide Web Database Access Program Puts Answer in Webpage

– Passes page to the server, which passes it to browser

Browser WebserverDatabase

Access Program

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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

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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

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Distributed Databases

Form 1

Form 2

Update

Update

Replicate

Replicate

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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

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Multimedia Databases

Graphics, sound, even video

Telephone Directory

Last name: Lee

First name: Pat

Extension: x6894

Pat’sphotowill gohere.

Pat’sphotowill gohere.

Click to hear Pat’sRecorded Greeting

Click to hear Pat’sRecorded Greeting

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Commercial Online Services

Provide For-Fee Information Usually Internet access too

(new)

UserPC &

Modem

UserPC &

Modem

CommercialOnlineService

CommercialOnlineService

WANWAN

Internal Services:Information

CommunicationProcessing

Internal Services:Information

CommunicationProcessing

The InternetThe Internet

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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?