W01 Two Tier Database Development

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Database Application DevelopmentDatabase Application DevelopmentEnvironmentEnvironment

Dr. Farhi MarirHead of the Knowledge Management Research Centre (KMC),

CCTM Department,

London Metropolitan University

30 January 2008 Copyright 2008 Dr. F. Marir2

Plan of the lecturePlan of the lecture

l Database Application Development Environment

l Client/Server Architecture

l Client/Server two tier architecture forDatabase Application Development

l ORACLE Development tools for DevelopingClient/Server two tier Database Application

l Limitation of Client Server two tierArchitecture and the Emergence of Threetier Architecture

l DB3012 Module Scheme of Work


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30 January 2008 Copyright 2008 Dr. F. Marir 3

Database ApplicationDatabase ApplicationDevelopment EnvironmentDevelopment Environment


Database application developmentDatabase application development

l A database application is any application thataccesses stored data and allows you to view,modify or manipulate that data.

l In most cases, the data is stored in a database.l A database application that requests information

from a data source such as a database is knownas a client applicationl A DBMS (Database Management System) that

handles data requests from various clients isknown as a database server

l There are different architecture environmentfor developing database application


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Architecture Environment for developingArchitecture Environment for developingdatabase applicationsdatabase applications

l There are at least three architectureEnvironment for database applicationdevelopment Mainframe architecture

File sharing architecture

Client/server architecture


Mainframe architectureMainframe architecture

l All intelligence is within the central hostcomputer

l Users interact with the host through a terminalthat captures keystrokes and sends thatinformation to the host

l Mainframe software architectures are not tied

to a hardware platforml User interaction can be done using PCs and UNIX

workstationsl A limitation of mainframe software

architectures: they do not easily support graphical user interfaces they do not access to multiple databases from

geographically dispersed sites.


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File Sharing ArchitectureFile Sharing Architecturel The original PC networks were based on file sharing

architectures, where the server downloads files from theshared location to the desktop environment.

l The requested user job is then run (including logic anddata) in the desktop environment.l File sharing architectures work if :

shared usage is low,

update contention is low, and the volume of data to be transferred is low.

l A limitation of file software architectures the capacity of the file sharing is strained when the number of

online user grew (it can only satisfy about 12 userssimultaneously)

graphical user interfaces (GUIs) became popular (makingmainframe and terminal displays appear out of date).


Client/Server ArchitectureClient/Server Architecture


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Client/Server ArchitectureClient/Server Architecture

l As a result of the limitations of file sharingarchitectures, the client/server architectureemerged

l The term client/server was first used in the 1980s inreference to personal computers (PCs) on a network

l This approach introduced a database server toreplace the file server

l Using a relational database management system,user queries could be answered directly using

Standard query language (SQL) statements ORRemote Procedure Calls (RPCs) which are typically usedto communicate between the client and server


Benefit of Client/ServerBenefit of Client/ServerArchitecture database DevelopmentArchitecture database Development

l It is a versatile, message-based and modularinfrastructure

l It is intended to improve usability, flexibility,interoperability, and scalability as compared to

centralised, mainframe, time sharing computingl It reduces network traffic by providing a query

response rather than total file transfer

l It also improves multi-user updating through aGraphical User Interface (GUI) front end to ashared database.


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Characteristics of a ClientCharacteristics of a Client

l Request sender is known as client

l

Initiates requestsl Waits for and receives replies.

l Usually connects to a small number ofservers at one time

l Typically interacts directly with end-usersusing a graphical user interface (GUI)


Characteristics of a ServerCharacteristics of a Server

l Receiver of request which is sent by client isknown as server

l Passive (slave)l Waits for requests from clients

l Upon receipt of requests, processes them andthen serves repliesl Usually accepts connections from a large number

of clientsl Typically does not interact directly with end-

users


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Client & Server locationsClient & Server locations

l One machine is devoted to Client andanother machine is devoted to Server

l Also a single machine can be both a clientand a server depending on the softwareconfiguration


An Example of Client/ServerAn Example of Client/ServerArchitectureArchitecture

l When you are visiting an e-commerce web site: your computer and web browser is the client,

the remote computers, databases, and applications which respondis the server.

When your web browser requests specific information from theonline store, the server finds all of the data in the database you

requested, assembles that data into a web page, and transmitsthat page back to your web browser for you to view.

l Specific types of clients include web browsers, emailclients, and online chat clients.

l Specific types of servers include web servers, ftpservers, application servers, database servers, mailservers, file servers, print servers, and terminal servers.

l Most web services are also types of servers.


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Type of Client/Server ArchitectureType of Client/Server Architecture

Client/Server architecture could bel Two tier Architecture

l Three tier Architecture is the mostcommonly used type of client-serverarchitecture

l Designs that contain more than two tiersare referred to as multi-tiered or n-tiered(n-tier).


Client/Server twoClient/Server two-- tiertier

ArchitectureArchitecture


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TwoTwo-- tier Client/Server Architecturetier Client/Server Architecture

l A two-tier client/server application architectureis implemented when a client talks directly to aserver, with no intermediate server.

l It is typically used in small environments of lessthan 50 users.l Generally two-tier architecture separates:

the user interface and the business logic (data logic) into onecomputer (Client or Tier1) and

the database management server is into another computer(Server or Tier2).

l The database management server provides storedprocedures and triggers.

l There are a number of software vendors e.g. ORACLE

which provide tools to simplify development of databaseapplications for the two tier client/server architecture


TwoTwo-- Tier Client/Server ArchitectureTier Client/Server Architecture


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ClientClient

UniversalUniversalDatabaseDatabase

Client/Server twoClient/Server two-- tier Benefitstier Benefits

Rich GUIMulti-Tasking

ReliabilityAvailabilityServiceability


ORACLE Tools for Developing twoORACLE Tools for Developing two--

tier Database Applicationtier Database Application


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l

Oracle Designer Oracle Developer

ORACLE tools for two- tierDatabase Application Development


ORACLE DesignerORACLE Designer

l It is used to design the database serverapplication

l It is used to create E-R diagrams, FunctionHierarchy diagrams, Process diagrams, and DataFlow diagrams that are needed to design a

database server and implement a user definedsystem in client's organizationl It provides a multi-user repository and is closely

integrated with ORACLE Forms and ReportDeveloper

l It allows organizations to design and rapidlydeliver scalable, database server application thatcan adapt to changing business needs.


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ORACLE Designer EditorORACLE Designer Editor


Creating the Entities RelationshipCreating the Entities RelationshipDiagram Using ORACLE DesignerDiagram Using ORACLE Designer


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Convert the ERD into an ORACLEConvert the ERD into an ORACLEdatabase tables using Databasedatabase tables using Database

Design TransformerDesign Transformer


ORACLE Developer SuiteORACLE Developer Suite

l It is a tool that helps you to create formsand reports based on the tables that youhave created using ORACLE Designer

l You can use Developer to:

Design and customize your forms and reports. Add various functionality, like radio buttons,

combo boxes, and list of values to make yourforms and reports more user friendly.

Write triggers on your objects to addfunctionality to them and capture errors.


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ORACLE Developer tool for theORACLE Developer tool for thedesign of Client Sidedesign of Client Side

Interactive Formsand Menus

Interactive Formsand Menus

ProfessionalReport andDatabasePublishing

ProfessionalReport andDatabasePublishing

Charting and

GraphicalApplications

Charting and

GraphicalApplications

PL/SQL Editing

and Debugging

PL/SQL Editing

and Debugging

Project

Management

ProjectManagement


Design Client Interface usingDesign Client Interface usingForm BuilderForm Builder


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Forms BuilderForms Builderfor Creating Client sidefor Creating Client side

l Graphical WYSIWYGEditors

l All standard GUIControls

l Complete Event Model

l Thin Client and WebDeployment

l Object Navigator

l Property Palettes

Reports Builder for Client sideReports Builder for Client side

l Graphical WYSIWYGEditors

l Multiple Formatssupported like

tabular and matrixl Standard output

formats includingHTML and PDFfor the Web

l Multi-Tier support


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Limitation of Client Server twoLimitation of Client Server twotier Architecturetier Architecture


TwoTwo-- tiers Client/Servertiers Client/ServerArchitecture LimitationArchitecture Limitation

l Client side presented two problems preventingtrue scalability:

Fat client, requiring considerable resources on clients computerto run effectively.

Significant client side administration overhead.

l

It has also a number of other limitations: When the number of users exceeds 100, performance begins todeteriorate.

Implementation of processing management services using vendorproprietary database procedures restricts flexibility and choiceof DBMS for applications.

Provide limited flexibility in moving (repartitioning) programfunctionality from one server to another without manuallyregenerating procedural code


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Three tier ArchitectureThree tier Architecture

l By 1995, three tier architecture wasproposed, each potentially running on adifferent platform.

l In the next lecture students will learnmore on three tier architecture andhow to develop it using ORACLE tools


Module Schedule of WorkModule Schedule of Work

from Week 1 to Week 1 2from Week 1 to Week 1 2


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W1 to W2 LecturesW1 to W2 Lectures

l Week 1 and Week 2 will focus on theintroduction of Database Application

Development in the two differentenvironments: Client/Server two tier architecture and

Client/Server three tier architecture


W3 to W7 Organisation of lectures,W3 to W7 Organisation of lectures,tutorials and Coursework 1tutorials and Coursework 1

l From Week 3 to Week 8 students will learn throughlectures and tutorials how to develop two-tier databaseapplications using ORACLE Designer, ORACLE DeveloperSuite and Procedural Language (PL)/SQL

l In particular the student will learn: How to design an ORACLE database (Server) using ORACLE

Designer How to design ORACLE forms and reports (Client) using ORACLE

Developer Suite How to write PL/SQL programs to develop interaction OR driven

events interface between Client and Database Server How to use SQL and PL/SQL to develop triggers which are

implicitly run, or fired, when and event happens

l Tutorial on Database Development in two tierarchitecture environment will start in week 2 till Week 7

l Coursework 1 will be given in week 2/3 and should besubmitted in week 9 and Demo of the CWK1 databaseapplication in Week11


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W8 to W12 Lectures, Tutorials andW8 to W12 Lectures, Tutorials andCoursework 2Coursework 2

l Lectures and tutorials will focus on

Database development in three tierarchitecture environment and also newtrends in database systems

l Coursework 2 will be given in Week 7 andshould be submitted in Week 12

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W01 Two Tier Database Development