1. Introduction to Web Applications Instructor: Enoch E. Damson

2. Information System A collection of components that work together to process data into accurate information using the information processing cycle Information processing cycle – involves: Input Processing Output Storage Introduction to the Web Applications2

3. Information System Components The main components of an information system are: Data – collected data and facts used as inputs for system processing Procedures – manual procedures, guidelines, business rules, and policies implemented in the system Hardware – computer systems and devices Software – applications, operating systems, and any other utilities used Network – communication infrastructure to connect client processes to the system People – users, managers, database administrators, programmers, systems analysts, systems administrators Introduction to the Web Applications3

4. Information System Components… Introduction to the Web Applications4

5. Information System Usage A collection of components that work together to process data into accurate information Can be categorized based on usage Lower-level management – uses information system to assist management and employees with operational tasks like inventory systems Middle-level management – uses information systems that deal with midterm goals like forecasting Upper-level management – works with information systems that assist with long-term decision-making goals Introduction to the Web Applications5

6. Information System Usage… Introduction to the Web Applications6

7. Information System Usage Categories Information systems are classified mainly into the following distinct categories based on their usage: Transaction-processing systems (TPS) – used for operational tasks like order tracking, customer service, payroll, etc Decision-support systems (DSS) – used for tactical management tasks like sales forecasting, risk management, etc Expert systems (ES) – captures reasoning of human experts like loan experts, market analysts, etc Introduction to the Web Applications7

8. Architecture High-level plan or strategy for building applications Can have a number of tiers (usually up to 5 tiers) The tiers may place data management, application logic, and the user interface into separate processes or combine them in some manner Introduction to the Web Applications8

9. One-Tier Architecture Combines data management, application logic, and the user interface into a single executable file Many old data processing applications like COBOL programs use this architecture Current desktop (PC) applications like MS Access applications also use this architecture Introduction to the Web Applications9

10. Two-Tier Architecture Organizes an application into two layers User interface layer Data management services layer The application/business logic may be in either or both layers Often used in conjunction with client-server computing which has: Clients – sends requests to the server Server – manages requests from clients Introduction to the Web Applications10

11. Three-Tier Architecture Cleanly separates data management, application logic, and the user interface into different layers User interface – manages forms and reports Data management – holds the database structure Application layer – holds the application logic Introduction to the Web Applications11

12. Tiered Architectures Introduction to the Web Applications12

13. Types of Applications Commonly used types of applications include: Client/server applications Data warehouse applications Web applications Introduction to the Web Applications13

14. Client/Server Applications Provide a flexible and scalable structure that takes advantage of the processing power of personal computers (PCs) utilizes the capacity and power of dedicated servers Introduction to the Web Applications14

15. Client/Server Architecture The typical client/server architecture is made up of: Server – providing services to clients Clients – requesting services from the server Business Logic – implementing business rules Introduction to the Web Applications15

16. Physical Architecture of Client/Server Applications Introduction to the Web Applications16

17. Data Warehouse Applications Used in decision-support applications to support executive management in decision-making processes The data warehouse is accessed by software applications or reporting applications called online analytical processing (OLAP) The OLAP applications retrieve data and generate reports with the capability of data mining Data warehouse – a collection of many types of data taken from a number of different databases that support various corporate departments Data mining – set of activities used to find new, hidden, or unexpected patterns in data within a data warehouse Introduction to the Web Applications17

18. Physical and Logical Architecture of Data Warehouse Applications Introduction to the Web Applications18

19. Web Applications Client/server applications accessed with a Web browser over a network like the Internet or an Intranet Web applications have become popular because of the: platform-independence of Web browsers and Web document formats ability to update and maintain Web applications without distributing and installing software on several client computers Introduction to the Web Applications19

20. Web Application Architecture Composed of: Web browser layer – allows users to navigate through Web pages on the Internet Web server layer – responds to requests submitted by the Web browsers Application server layer – used for data processing and interfacing to the business logic and database server Business Logic layer – implements business rules Database server layer – stores and manages data Introduction to the Web Applications20

21. Web Application Architecture… Uses Web browsers as the front ends Uses the Web to communicate with the Web server Uses HTTP as the communication protocol between the Web browser and the Web server Uses HTML/XHTML pages created using, ActiveX, Java applets, ASP, JSP etc Introduction to the Web Applications21

22. Web Application Components Logical components of Web Applications Physical structure of Web Applications Introduction to the Web Applications22

23. Examples of Web Applications Examples of Web applications include: Reservation systems Weblogs Massively-Multiplayer Online Role-Playing Game (MMORPG) Online shopping Online auction Games Multimedia applications Calendars Maps Chat applications Clocks Interactive design applications Stock tickers Currency converters Data entry/display systems Introduction to the Web Applications23

24. Nature of Web Applications Web applications: have features and benefits of desktop applications have some form of programmatic control either on the client side, or on the server, or both emphasize on real data separation as opposed to markup/style separation are usually smaller in file size than desktop applications can have rich graphical-user interfaces (GUI) have reduced client-requirements have portable data Introduction to the Web Applications24

25. Building Web Applications Two major components needed to build web applications include: Hardware platforms – could be a single shared server running on a web server and a database Software platforms Schema – for data storage Business rule (logic) – for accessing and modifying data Interactive logic – for presenting data to users Introduction to the Web Applications25