Download ADVANCED WEB DESIGN AND DEVELOPEMENT and more Lecture notes Information Technology in PDF only on Docsity!
Mount Kenya University
P.O. Box 342-01000 Thika
Web: www.mku.ac.ke
DEPARTMENT OF INFORMATION
TECHNOLOGY
COURSE CODE: BIT 3207
COURSE TITLE: ADVANCED WEB DESIGN AND
DEVELOPMENT FOR BUSINESS WORLD
Instructional manual for BBIT – Distance Learning
By David Kibaara
TABLE OF CONTENT
- 1 COURSE OUTLINE.................................................................................................................
- 2 CHAPTER ONE: INTRODUCTION TO ADVANCED WEB DESIGN AND DEVELOPMENT CONCEPTS.....
- 2.1 Learning Objec�ves:............................................................................................................
- 2.2 By the end of this chapter the learner shall be able to;.......................................................
- 2.3 1.1 Networking fundamentals..............................................................................................
- 2.3.1 1.1.1 Proper�es of a computer network.................................................................
- 2.3.2 1.1.2 TCP/IP model..................................................................................................
- 2.3.3 1.1.3 Internet socket...............................................................................................
- 2.3.4 1.1.4 Hypertext Transfer Protocol (HTTP)................................................................
- 2.4 1.2 Client-side components..................................................................................................
- 2.4.1 1.2.1 Hypertext Markup Language (HTML).............................................................
- 2.4.2 1.2.2 Extensible Markup Language (XML)...............................................................
- 2.4.3 1.2.3 Web browser..................................................................................................
- 2.4.4 1.2.4 Applet.............................................................................................................
- 2.5 1.3 Server-side component..................................................................................................
- 2.5.1 1.3.1 Web server.....................................................................................................
- 2.5.2 1.3.2 Servlet............................................................................................................
- 2.5.3 1.3.3 JavaServer Pages (JSP)....................................................................................
- 2.6 1.4 Database components...................................................................................................
- 2.6.1 1.4.1 Database Management System (DBMS).........................................................
- 2.6.2 1.4.2 Structured Query Language (SQL)
- 2.6.3 1.4.3 Database server..............................................................................................
- 2.6.4 1.4.4 Java Database Connec�vity............................................................................
- 2.7 Chapter Review Ques�ons...................................................................................................
- 2.8 References...........................................................................................................................
- 3 CHAPTER TWO: ARCHITECTURE AND DESIGN......................................................................
- 4.1 Learning Objec�ves:............................................................................................................
- 4.2 By the end of this chapter the learner shall be able to;.......................................................
- 4.3 2.1 Mul��er architecture.....................................................................................................
- 4.4 2.1.1 Three-�er architecture................................................................................................
- 4.4.1 2.1.2Web development usage................................................................................
- 4.5 2.2 Interfacing to legacy systems
- 4.5.1 2.2.1 Legacy system................................................................................................
- 4.5.2 2.2.2 Organiza�ons can have compelling reasons for keeping a legacy system, such as:.......
- 4.5.3 2.2.3 Reasons why Legacy systems are considered problema�c by so�ware engineers:.......
- 4.5.4 2.3.4 Process of Interfacing new to legacy systems
- 4.5.5 2.3.5 Analyzing Legacy Data Sources.......................................................................
- 4.5.6 2.3.6 Analyzing Legacy Code...................................................................................
- 4.6 2.4 Object-oriented modeling for web applica�ons.............................................................
- 4.6.1 2.4.1 Object-oriented programming (OOP).............................................................
- 4.7 2.5 Unified Modeling Language...........................................................................................
- 4.7.1 2.5.1 UML Diagrams................................................................................................
- 4.8 Chapter Review Ques�ons...................................................................................................
- 4.9 References...........................................................................................................................
- 5 CHAPTER THREE: ACTIVE SERVER PAGES (ASP)....................................................................
- 5.1 Learning Objec�ves:............................................................................................................
- 5.2 By the end of this chapter the learner shall be able to;.......................................................
- 5.3 3.1 Introduc�on to ASP........................................................................................................
- 5.3.1 3.1.1 What is ASP?..................................................................................................
- 5.3.2 3.1.2 ASP Compa�bility...........................................................................................
- 5.3.3 3.1.3 What is an ASP File?.......................................................................................
- 5.3.4 3.1.4 How Does ASP Differ from HTML?..................................................................
- 5.3.5 3.1.5 What can ASP do for you?..............................................................................
- 5.3.6 3.1.6 IIS - Internet Informa�on Server.....................................................................
- 5.3.7 3.1.7 PWS - Personal Web Server............................................................................
- 5.4 3.2 Running and Installing ISS in your machine....................................................................
- 5.4.1 3.2.1 Your Windows PC as a Web Server.................................................................
- 5.4.2 3.2.2 How to Install IIS on Windows 7 and Windows Vista......................................
- 5.4.3 3.2.3 How to Install IIS on Windows XP and Windows 2000...................................
- 5.4.4 3.2.4 Test Your Web.................................................................................................
- 5.5 3.3 ASP Basic Syntax Rules...................................................................................................
- 5.5.1 3.3.1 Write Output to a Browser.............................................................................
- 5.5.2 3.3.2 Using VBScript in ASP.....................................................................................
- 5.5.3 3.3.3 Using JavaScript in ASP...................................................................................
- 5.5.4 3.3.4 Add some HTML tags to a text.......................................................................
- 5.6 3.4 ASP Variables..................................................................................................................
- 5.6.1 3.4.1 Declare a variable...........................................................................................
- 5.6.2 3.4.2 Declare an array.............................................................................................
- 5.6.3 3.4.3 Loop through the HTML headings..................................................................
- 5.6.4 3.4.4 Time-based gree�ng using VBScript...............................................................
- 5.6.5 3.4.5 Time-based gree�ng using JavaScript.............................................................
- 5.6.6 3.4.6 Life�me of Variables.......................................................................................
- 5.7 3.5 ASP Procedures..............................................................................................................
- 5.7.1 3.5.1 Procedures.....................................................................................................
- 5.7.2 3.5.2 Differences between VBScript and JavaScript................................................
- 5.7.3 3.5.3 Call procedures using VBScript.......................................................................
- 5.8 3.6 ASP Forms and User Input..............................................................................................
- 5.8.1 3.6.1 User Input......................................................................................................
- 5.8.2 3.6.2 Request.QueryString......................................................................................
- 5.8.3 3.6.3 Request.Form.................................................................................................
- 5.8.4 3.6.4 Form Valida�on..............................................................................................
- 5.8.5 3.6.5 A form with method="get".............................................................................
- 5.8.6 3.6.6 A form with method="post"...........................................................................
- 5.8.7 3.6.8 A form with radio bu�ons..............................................................................
- 5.9 3.7 ASP Condi�onal Statements...........................................................................................
- 5.9.1 3.7.1 The If...Then Statement..................................................................................
- 5.9.2 3.7.2 The If...Then...Else Statement.........................................................................
- 5.9.3 3.7.3 The If...Then...ElseIf Statement.......................................................................
- 5.9.4 3.7.4 The Select Case Statement.............................................................................
- 5.10 3.8 ASP Loops
- 5.10.1 3.8.1 The Do...While Loop.......................................................................................
- 5.10.2 3.8.2 The Do...Loop...While Statement...................................................................
- 5.10.3 3.8.3 The Do...Un�l...Loop Statement.....................................................................
- 5.10.4 3.8.4 The Do...Loop...Un�l Statement.....................................................................
- 5.11 3.9 ASP Loop Counters.........................................................................................................
- 5.11.1 3.9.1 The For...To...Next Loop..................................................................................
- 5.11.2 3.9.2 Stepping the Coun�ng Loop...........................................................................
- 5.12 3.10 ASP Cookies..................................................................................................................
- 5.12.1 3.10.1 How to Create a Cookie?..............................................................................
- 5.12.2 3.10.2 How to Retrieve a Cookie Value?..................................................................
- 5.12.3 3.10.3 A Cookie with Keys.......................................................................................
- 5.12.4 3.10.4 Read all Cookies...........................................................................................
- 5.12.5 3.10.5 What if a Browser Does NOT Support Cookies?...........................................
- 5.12.6 1. Add parameters to a URL....................................................................................
- 5.12.7 2. Use a form...........................................................................................................
- 5.13 3.11 ASP Session Object.......................................................................................................
- 5.13.1 3.11.1 The Session object
- 5.13.2 3.11.2 When does a Session Start?.........................................................................
- 5.13.3 3.11.3 When does a Session End?...........................................................................
- 5.13.4 3.11.4 Store and Retrieve Session Variables
- 5.13.5 3.11.5 Remove Session Variables
- 5.13.6 3.11.6 Loop Through the Contents Collec�on.........................................................
- 5.13.7 3.11.7 Loop Through the Sta�cObjects Collec�on..................................................
- 5.14 3.12 ASP Applica�on Object.................................................................................................
- 5.14.1 3.12.1 Applica�on Object........................................................................................
- 5.14.2 3.12.2 Store and Retrieve Applica�on Variables.....................................................
- 5.14.3 3.12.3 Loop Through the Contents Collec�on.........................................................
- 5.14.4 3.12.4 Loop Through the Sta�cObjects Collec�on..................................................
- 5.14.5 3.12.5 Lock and Unlock...........................................................................................
- 5.15 3.13 ASP Including Files.......................................................................................................
- 5.15.1 3.13.1 The #include Direc�ve..................................................................................
- 5.15.2 3.13.2 How to Use the #include Direc�ve...............................................................
- 5.15.3 3.13.3 Syntax for Including Files.............................................................................
- 5.15.4 3.13.4 The Virtual Keyword.....................................................................................
- 5.15.5 3.13.5 The File Keyword..........................................................................................
- 5.16 3.14 ASP The Global.asa file.................................................................................................
- 5.16.1 3.14.1 The Global.asa file........................................................................................
- 5.16.2 3.14.2 Events in Global.asa.....................................................................................
- 5.16.3 3.14.3 Declara�ons...................................................................................
- 5.16.4 Examples.................................................................................................................
- parameter:................................................................................................................................ 5.16.5 The first example creates an object of session scope named "MyAd" by using the ProgID
- 5.16.6 .
- 5.16.7 .................................................................................................................
- using the ClassID parameter:.................................................................................................... 5.16.8 The second example creates an object of applica�on scope named "MyConnec�on" by
- 5.16.9 ................................
- 5.16.11 .................................................................................................................
- 5.16.12 The objects declared in the Global.asa file can be used by any script in the applica�on:........
- 5.16.13 GLOBAL.ASA:...........................................................................................................
- 5.16.14 .
- 5.16.15 .................................................................................................................
- 5.16.16 You could reference the object "MyAd" from any page in the ASP applica�on:.....
- 5.16.17 SOME .ASP FILE:......................................................................................................
- 5.16.18 <%=MyAd.GetAdver�sement("/banners/adrot.txt")%>..........................................
- 5.16.19 3.14.4 TypeLibrary Declara�ons..............................................................................
- 5.16.20 3.15.5 Error Values..................................................................................................
- 5.17 Restric�ons..........................................................................................................................
- 5.17.1 3.14.6 How to use the Subrou�nes.........................................................................
- 5.17.2 3.14.7 Global.asa Example......................................................................................
- 5.18 3.15 ASP Sending e-mail with CDOSYS.................................................................................
- 5.18.1 3.15.1 Sending e-mail with CDOSYS........................................................................
- 5.18.2 3.15.2 How about CDONTs?....................................................................................
- 5.19 3.16 Object-Oriented Programming in ASP..........................................................................
- 5.19.1 3.16.1 Class Declara�on..........................................................................................
- 5.19.2 3.16.2 Using a Class.................................................................................................
- 5.19.3 3.16.3 Member Variables........................................................................................
- 5.19.4 3.16.4 Constructors.................................................................................................
- 5.19.5 3.16.5 Methods.......................................................................................................
- 5.19.6 3.16.6 Proper�es.....................................................................................................
- 5.19.7 3.16.7 Summary......................................................................................................
- 5.20 Chapter Review Ques�ons...................................................................................................
- 5.21 References...........................................................................................................................
- 6 CHAPTER FOUR: SAMPLE PAPERS.........................................................................................
COURSE OUTLINE
BIT 3207: ADVANCED WEB DESIGN AND DEVELOPMENT FOR BUSINESS WORLD
Contact Hours: 42
Pre-requisite: BIT 2105 - INTRODUCTION TO WEB DESIGN AND DEVELOPMENT
Lecturer: Mr. Kibaara
Purpose: To acquire advanced web technologies for advanced web systems
Objectives: By the end of the course unit the learner should:
- Be introduced to advanced technologies used to build the world wide web (WWW) commonly applied in business
- Develop an advanced business website with transactional capacity Course Assessments: Continuous Assessment Tests 30%
End of semester examination 70%
Teaching/Learning Methodology: Lectures, Tutorials, Computer laboratory
Instructional Materials/Equipment: Audio visual aids, Computer laboratory, Internet Access
Required Textbooks:
Morrison M.c.Morrison J. (2000), Databas driven website, Thomas learning
Textbooks for Further reading:
Wilide E wilde’s W.W.W.(1999), Technical Foundation of the W.W.W., Springer
ADVANCED WEB DESIGN AND DEVELOPMENT FOR BUSINESS WORLD - TOPICS –
Details
Week 1: Introduction
- Networking fundamentals
- Client-side components
- Server-side component
- Database components
- Classes, objects, inheritance
Module Compiler: David Kibaara
CHAPTER ONE: INTRODUCTION TO ADVANCED WEB
DESIGN AND DEVELOPMENT CONCEPTS
Learning Objectives:
By the end of this chapter the learner shall be able to; i. Explain the networking fundamentals and TCP/IP protocol suite ii. Explain the components in the client side and server side
1.1 Networking fundamentals
A computer network is a collection of hardware components and computers interconnected by communications channels that allow sharing of resources and information. The rules and data formats for exchanging information in a computer network are defined by communications protocols.
1.1.1 Properties of a computer network
- Facilitate communications - Using a network, people can communicate efficiently and easily via email, instant messaging, chat rooms, telephone, video telephone calls, and video conferencing.
- Permit sharing of files, data, and other types of information - In a network environment, authorized users may access data and information stored on other computers on the network. The capability of providing access to data and information on shared storage devices is an important feature of many networks.
- Share network and computing resources - In a networked environment, each computer on a network may access and use resources provided by devices on the network, such as printing a document on a shared network printer. Distributed computing uses computing resources across a network to accomplish tasks.
- May be insecure - A computer network may be used by computer hackers to deploy computer viruses or computer worms on devices connected to the network, or to prevent these devices from normally accessing the network (denial of service).
1.1.2 TCP/IP model
The TCP/IP model is a description framework for computer network protocols created in the 1970s by DARPA, an agency of the United States Department of Defense. It evolved from ARPANET, which were the world's first wide area network and a predecessor of the Internet.
A socket address is the combination of an IP address (the location of the computer) and a port (which is mapped to the application program process) into a single identity, much like one end of a telephone connection is the combination of a phone number and a particular extension.
1.1.4 Hypertext Transfer Protocol (HTTP)
The Hypertext Transfer Protocol (HTTP) is a networking protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web. The standards development of HTTP has been coordinated by the Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C).
HTTP functions as a request-response protocol in the client-server computing model. In HTTP, a web browser, for example, acts as a client, while an application running on a computer hosting a web site functions as a server. The client submits an HTTP request message to the server. The server, which stores content, or provides resources, such as HTML files, or performs other functions on behalf of the client, returns a response message to the client. A response contains completion status information about the request and may contain any content requested by the client in its message body.
A web browser (or client) is often referred to as a user agent (UA). Other user agents can include the indexing software used by search providers, known as web crawlers, or variations of the web browser such as voice browsers, which present an interactive voice user interface.
The HTTP protocol is designed to permit intermediate network elements to improve or enable communications between clients and servers. High-traffic websites often benefit from web cache servers that deliver content on behalf of the original, so-called origin server, to improve response time. HTTP proxy servers at network boundaries facilitate communication when clients without a globally routable address are located in private networks by relaying the requests and responses between clients and servers.
HTTP is an Application Layer protocol designed within the framework of the Internet Protocol Suite. The protocol definitions presume a reliable Transport Layer protocol for host-to-host data transfer. The Transmission Control Protocol (TCP) is the dominant protocol in use for this purpose. However, HTTP has found application even with unreliable protocols, such as the User Datagram Protocol (UDP) in methods such as the Simple Service Discovery Protocol (SSDP).
HTTP Resources are identified and located on the network by Uniform Resource Identifiers (URIs)—or, more specifically, Uniform Resource Locators (URLs)—using the http or https URI schemes. URIs and the Hypertext Markup Language (HTML), form a system of inter-linked resources, called hypertext documents, on the Internet, that led to the establishment of the World Wide Web in 1990 by English physicist Tim Berners-Lee.
1.2 Client-side components
Client-side refers to operations that are performed by the client in a client–server relationship in a computer network.
Typically, a client is a computer application, such as a web browser, that runs on a user's local computer or workstation and connects to a server as necessary. Operations may be performed client-side because they require access to information or functionality that is available on the client but not on the server, because the user needs to observe them or provide input, or because the server lacks the processing power to perform the operations in a timely manner for all of the clients it serves. Additionally, if operations can be performed by the client, without sending data over the network, they may take less time, use less bandwidth, and incur a lesser security risk.
When the server serves data in a commonly used manner, for example according to the HTTP or FTP protocols, users may have their choice of a number of client programs. In the case of more specialized applications, programmers may write their own server, client, and communications protocol that can only be used with one another.
Programs that run on a user's local computer without ever sending or receiving data over a network are not considered clients, and so the operations of such programs would not be considered client-side operations.
1.2.1 Hypertext Markup Language (HTML)
Hypertext Markup Language (HTML) is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpage’s. HTML is written in the form of HTML elements consisting of tags, enclosed in angle brackets (like ), within the web page content. HTML tags normally come in pairs like and . The first tag in a pair is the start tag, the second tag is the end tag (they are also called opening tags and closing tags). In between these tags web designers can add text, tables, images, etc.
The purpose of a web browser is to read HTML documents and compose them into visible or audible web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page. HTML elements form the building blocks of all websites. HTML allows images and objects to be embedded and can be used to create interactive forms. It provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. It can embed scripts in languages such as JavaScript which affect the behavior of HTML webpage’s.
Web browsers can also refer to Cascading Style Sheets (CSS) to define the appearance and layout of text and other material. The W3C, maintainer of both the HTML and the CSS standards, encourages the use of CSS over explicitly presentational HTML markup.
- 3D modeling display applets, used to rotate and zoom a model
- Browser games can be applet-based, though some may develop into fully functional applications that require installation.
1.3 Server-side component
Server-side refers to operations that are performed by the server in a client–server relationship in computer networking. Typically, a server is a software program, such as a web server, that runs on a remote server, reachable from a user's local computer or workstation. Operations may be performed server-side because they require access to information or functionality that is not available on the client, or require typical behavior that is unreliable when it is done client-side.
Server-side operations also include processing and storage of data from a client to a server, which can be viewed by a group of clients. Advantage: This lightens the work of your client.
1.3.1 Web server
Web server can refer to either the hardware (the computer) or the software (the computer application) that helps to deliver content that can be accessed through the Internet. The most common use of web servers is to host web sites but there are other uses like data storage or for running enterprise applications.
1.3.2 Servlet
A servlet is a Java programming language class used to extend the capabilities of servers that host applications accessed via a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by Web servers. Thus, it can be thought of as a Java Applet that runs on a server instead of a browser.
1.3.3 JavaServer Pages (JSP)
JavaServer Pages (JSP) is a Java technology that helps software developers serve dynamically generated web pages based on HTML, XML, or other document types. Released in 1999 as Sun's answer to ASP and PHP, JSP was designed to address the perception that the Java programming environment didn't provide developers with enough support for the Web. To deploy and run, a compatible web server with servlet container is required. The Java Servlet and the JavaServer Pages (JSP) specifications from Sun Microsystems and the JCP (Java Community Process) must both be met by the container.
1.4 Database components
A database is an organized collection of data for one or more purposes, usually in digital form. The data is typically organized to model relevant aspects of reality (for example, the availability of rooms in hotels),
in a way that supports processes requiring this information (for example, finding a hotel with vacancies). The term "database" refers both to the way its users view it, and to the logical and physical materialization of its data, content, in files, computer memory, and computer data storage. This definition is very general, and is independent of the technology used. However, not every collection of data is a database; the term database implies that the data is managed to some level of quality (measured in terms of accuracy, availability, usability, and resilience) and this in turn often implies the use of a general- purpose Database management system (DBMS). A general-purpose DBMS is typically a complex software system that meets many usage requirements, and the databases that it maintains are often large and complex. The utilization of databases is widely spread to a degree that virtually any technology and product nowadays relies on databases and DBMSs for its development and commercialization, or even may have such embedded in it. Also organizations and companies, from small to very large, heavily depend on databases for their operations.
1.4.1 Database Management System (DBMS)
A database management system (DBMS) is a software package with computer programs that control the creation, maintenance, and the use of a database. It allows organizations to conveniently develop databases for various applications by database administrators (DBAs) and other specialists. A DBMS allows different user application programs to concurrently access the same database. DBMSs may use a variety of database models, such as the relational model or object model, to conveniently describe and support applications. It typically supports query languages, which are in fact high-level programming languages, dedicated database languages that considerably simplify writing database application programs. Database languages also simplify the database organization as well as retrieving and presenting information from it. A DBMS provides facilities for controlling data access, enforcing data integrity, managing concurrency control, recovering the database after failures and restoring it from backup files, as well as maintaining database security.
1.4.2 Structured Query Language (SQL)
SQL is a programming language designed for managing data in relational database management systems (RDBMS). Originally based upon relational algebra and tuple relational calculus, its scope includes data insert, query, update and delete, schema creation and modification, and data access control.
1.4.3 Database server
A database server is a computer program that provides database services to other computer programs or computers, as defined by the client–server model. The term may also refer to a computer dedicated to running such a program. Database management systems frequently provide database server functionality, and some DBMSs (e.g., MySQL) rely exclusively on the client–server model for database access. Such a server is accessed either through a "front end" running on the user’s computer which displays requested data or the "back end" which runs on the server and handles tasks such as data analysis and storage.
CHAPTER TWO: ARCHITECTURE AND DESIGN
Learning Objectives:
By the end of this chapter the learner shall be able to; i. Explain the multitier internet architecture ii. Understand legacy systems and how to integrate them with current systems iii. Understand object oriented modeling for the internet
2.1 Multitier architecture
In software engineering, multi-tier architecture (often referred to as n-tier architecture) is a client–server architecture in which the presentation, the application processing, and the data management are logically separate processes. For example, an application that uses middleware to service data requests between a user and a database employs multi-tier architecture. The most widespread use of multi-tier architecture is the three-tier architecture. N-tier application architecture provides a model for developers to create a flexible and reusable application. By breaking up an application into tiers, developers only have to modify or add a specific layer, rather than have to rewrite the entire application over. There should be a presentation tier, a business or data access tier, and a data tier. The concepts of layer and tier are often used interchangeably. However, one fairly common point of view is that there is indeed a difference, and that a layer is a logical structuring mechanism for the elements that make up the software solution, while a tier is a physical structuring mechanism for the system infrastructure.
2.1.1 Three-tier architecture
Three-tier is a client–server architecture in which the user interface, functional process logic ("business rules"), computer data storage and data access are developed and maintained as independent modules, most often on separate platforms. The three-tier model is software architecture and a software design pattern. Apart from the usual advantages of modular software with well-defined interfaces, the three-tier architecture is intended to allow any of the three tiers to be upgraded or replaced independently as requirements or technology change. For example, a change of operating system in the presentation tier would only affect the user interface code.
Typically, the user interface runs on a desktop PC or workstation and uses a standard graphical user interface, functional process logic may consist of one or more separate modules running on a workstation or application server, and an RDBMS on a database server or mainframe contains the computer data storage logic. The middle tier may be multi-tiered itself (in which case the overall architecture is called an "n-tier architecture").
Three-tier architecture has the following three tiers:
- Presentation tier - This is the topmost level of the application. The presentation tier displays information related to such services as browsing merchandise, purchasing, and shopping cart contents. It communicates with other tiers by outputting results to the browser/client tier and all other tiers in the network.
- Application tier (business logic, logic tier, data access tier, or middle tier) - The logic tier is pulled out from the presentation tier and, as its own layer, it controls an application’s functionality by performing detailed processing.
- Data tier - This tier consists of database servers. Here information is stored and retrieved. This tier keeps data neutral and independent from application servers or business logic. Giving data its own tier also improves scalability and performance.
2.1.2Web development usage
In the web development field, three-tier is often used to refer to websites, commonly electronic commerce websites, which are built using three tiers:
- A front-end web server serving static content, and potentially some cached dynamic content. In web based application, Front End is the content rendered by the browser. The content may be static or generated dynamically.
- A middle dynamic content processing and generation level application server, for example Java EE, ASP.NET, PHP, ColdFusion platform.
- A back-end database, comprising both data sets and the database management system or RDBMS software that manages and provides access to the data.
2.2 Interfacing to legacy systems
2.2.1 Legacy system
