the system aims at the maintenance and

8/14/2019 The System Aims at the Maintenance And

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E-Zest


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Chapter 1


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Abstract


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The system aims at the maintenance and management of the different

accommodations that are available in the different parts of the world.

It mainly takes care of the resort management at the core area of the

database. The system provides the information regarding the

different resorts that are available and their status specific to

availability. The database also manages the atomic information

regarding the different units that are available under one resort and

the architectural details of the Unit facilities that are available. Each

unit is well furnished and is well designed for the basic flexibility of

the tourists who are expected to stay.

The guests can visit the site and register themselves with the required

information that is expected by the system. Each registered guest

can raise a request for the unit bookings. The Guests are scheduled

with the information of the availability of the units for they have

requested the time. The Units maintenance is automated for proper

management of the availability status of the units or the scheduled

expected date of their availability in near future. The system provides

the facility for booking of the required available units as per the

number that is available.

The system totally built upon the standards of Three Tier Architecture with

Client, Business and Data Tiers associated as separate layers, with

specification to high cohesion and loose Coupling Standards for easy

maintenance.


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The entire project has been develped keeping in view of the Distributed client

server computing technology in mind.The specification have been

normalized upto 3NF to eliminate all the anomalies that may arise

due to the database transactions that are executed by the actual

administration and users.The user interfaces are browser specific to

give distributed accessability for the overall system.The internal

database has beeb selected as Oracle 8i.The basic constructs of the

tablespaces, clusters and indexes have been exploited to provide

higher consistency and reliability for the data storage.The oracle 9i

was a choice as it provides the constructs of high level reliabiity and

security.The total front end was dominated using HTML standards

applied with the dynamism of JAVA server pages. Thecommunicatin

client was designed using servlets and JSPs. At all proper levels high

care was taken to check that the system manages the date

consistency with proper business validations.The database

connectivity was planned using the Java DataBase Connectivity,the

authorization and authorization was cross checked at all stages.The

user level accessabiity has been restricted into two zones the

administrative and the normal user zone.

The Bean components have been implemented for proper reusability and

authenticity. The standards of security and date portative mechanism

have been given a big choice for proper usage. The application takes

care of different modules and their associated reports which re

produced as per the applicable strategies and standards that are put

forwarded by the administrative staff..


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Chapter 2


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Introduction


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The entire project has been develped keeping in view of the Distributed client

server computing technology in mind.The specification have been normalized

upto 3NF to eliminate all the anomalies that may arise due to the database

transactions that are executed by the actual administration and users.The

user interfaces are browser specific to give distributed accessability for the

overall system.The internal database has beeb selected as Oracle 8i.The

basic constructs of the tablespaces,clusters and ridexes have been exploited

to provide higher consistency and reliability for the data storage.The oracle 8i

was a choice as it provides the constructs of high level reliabiity and

security.The total front end was dominated using HTML standards applied

with the dynamism of JAVA server pages. Thecommunicatin client was

designed using servlets. At all proper levels high care was taken to checkthat the system manages the date consistency with proper business

validations.The database connectivity was planned using the Java DataBase

Connectivity,the authorization and authorization was cross checked at all

stages.The user level accessabiity has been restricted into two zones the

administrative and the normal user zone.


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About the Organization


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Existing Process:

Guest Visits anyNearest Hostel or

Motel

Raiser hisRequest at the

Clerk for

Accommodation

Clerk Searchesthe requiredledgers for

availability

If not Available

IF available put

the info at theguest ViewGuest may

compromise withhis requirment

Guest Check the

requiredParameters as

per his

Convenience

Guest Not

Compromised

If Provided planhis stay

Leaves fnAnother System


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Proposed System:

The Automated system with distributed architecture can support issues like.

1) The system maintains the different location that are available and

registered in a central DB, which leads easy accessibility and consistency.

2) Each Accommodation available units and all the unit facilities are also

available at the click of a mouse.

3) The registration of new guest is online house new guest can make

them they convenient for registration process on the basic of

24x7x326days.

4) The Units can be booked by the Registered guest irrespective of the

Geographical barriers.

5) The Guest are provided with upto minute information related to the

unit availability and their status. From their convenient place.

6) The decision process in more fastes and more consistent.

7) The guest have information at their demand related to any unit status

of their own unit booking status.


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Chapter 3


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FeasibilityReport


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System Analysis Concentration:

Before planning a replacing for a new system it is essential to have through

knowledge about the existing system along with estimation of how lost

computes can be used to make its operations more effective.

System analysis is the process of collecting and interpreting facts, disposing

problem and use the information about the existing system, which is also

called as system study.

System analysis is about understanding situation but not solving the

problem.

System analysis is performed to determine whether a not it is feasible to

design and information system laved on the policies and plans of an

organization. To determine the user requirements and to eliminate the

weakness of the present system a few general requirements are concerned.

GENERAL REQUIREMENTS:

The new system should be cost effective

To improve productivity and service and service.

To enhance user interface.To improve information presentation and durability.

To upgrade systems reliability, availability and flexibility.

To address human factors for better and uses acceptance.

PROBLEM IN THE CURRENT SYSTEM:

The present system is presently is an undeveloped form and the manual

process of the overall system is too clumsy and complicated. The clients in

the real time consultancy system can be too thick and may need many

resources to be used upon the system. If the system is developed, in a

distributed over interface with centralized database is the only solution.


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Feasibility Report

TECHINICAL FEASIBILITY:

Evaluating the technical feasibility is the trickiest part of a feasibility study.

This is because, at this point in time, not too many detailed design of the

system, making it difficult to access issues like performance, costs on (on

account of the kind of technology to be deployed) etc. A number of issues

have to be considered while doing a technical

analysis.

Understand the different technologies involved in the proposed system:

Before commencing the project, we have to be very clear about what are the

technologies that are to be required for the development of the new system.

Find out whether the organization currently possesses the required

technologies:

Is the required technology available with the organization?

If so is the capacity sufficient?

For instance Will the current printer be able to handle the new reports and forms

required for the new system?


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OPERATIONAL FEASIBILITY:

Proposed projects are beneficial only if they can be turned into information

systems that will meet the organizations operating requirements. Simply

stated, this test of feasibility asks if the system will work when it is

developed and installed. Are there major barriers to Implementation? Here

are questions that will help test the operational feasibility of a project:

Is there sufficient support for the project from management from users? If

the current system is well liked and used to the extent that persons will not

be able to see reasons for change, there may be resistance.

Are the current business methods acceptable to the user? If they are not,

Users may welcome a change that will bring about a more operational and

useful systems.

Have the user been involved in the planning and development of the project?

Early involvement reduces the chances of resistance to the system and in

General and increases the likelihood of successful project.

Since the proposed system was to help reduce the hardships encountered. In

the existing manual system, the new system was considered to be

operational feasible.

ECONOMIC FEASIBILITY:

Economic feasibility attempts 2 weigh the costs of developing and

implementing a new system, against the benefits that would accrue from

having the new system in place. This feasibility study gives the top

management the economic justification for the new system.

A simple economic analysis which gives the actual comparison of costs and

benefits are much more meaningful in this case. In addition, this proves to

be a useful point of reference to compare actual costs as the project

progresses. There could be various types of intangible benefits on account of

automation. These could include increased customer satisfaction,


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improvement in product quality better decision making timeliness of

information, expediting activities, improved accuracy of operations, better

documentation and record keeping, faster retrieval of information, better

employee morale.

a) Technical Description

Databases: The total number of databases that were identified to build the

system is 10.The major part of the Databases is categorized as

Administrative components and the user components. The administrative

components are useful is managing the actual master data that may; be

necessary to maintain the consistency of the system. The administrative

databases are purely used for the internal organizational needs and

necessities. The user components are designed to handle the transactional

state that arise upon the system whenever the general client makes a visit

onto the system for the sake of the report based information. The user

components are scheduled to accept parametrical information for the user as

per the systems necessity.

GUIs

For the flexibility of the user, the interface has been developed in graphical

user interface mode. The normal interface is applied through browser.

The GUIs at the top level has been categorized as:

1) Administrative user interface

2) Customer or general user interface

The administrative user interface concentrates on the consistent information

that is practically, pact of the organizational activities and which needs

proper authentication for the data collection. The interfaces help the visitors

with all the transactional states like Data insertion, Data deletion and Data

updating with the data search capabilities.


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The general user interface helps the users upon the system in transactions

through the required services that are provided upon the system. The

general user interface also helps the ordinary user is managing their own

information in a customized manner as per their flexibilities.

Feasibility

(i) Technical Feasibility

The system is self-explanatory and does not need any entire sophisticated

training. The system has been built by concentrating on the graphical user

interface concepts; the application can also be handled very easily with a

novice user. The overall time that a user needs to get trained is less than 15

minutes.

The system has been added with features of menu driven and button

interaction methods, which makes him the master as he starts working

through the environment. As the software that was used for developing thisapplication are very economical and are readily available is the market the

only time that is lost by the customer is just installation time.

Time Based:

In this world of busy schedule with which the industrial professionals are

getting through this kind of system is a boon for the kind of information they

can readily access at the tip of their fingers. The Tourist, who intends to

make a visit to the specific choice of his place, need not enquire about the

details taking the entire pin physically. The Tourist can just get himself

connected to the site at his own desk with the respective URL that has been

allocated for him and can make a wide variety of choices for the


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accommodations that are available in the central repository of the existing

database. The User can have the information of all the units that are

practically registered along with the facilities that are available with respect

to every unit. The guest is given free hands to register his information as per

the practical requirements of the site, such that he can be tracked and

provided services at the demand that is raised by him.

The Guest once registered can make multiple visits upon the site as per his

requirements and enquire for the units availability and the status of his

previous bookings, if any.

The Administrators can make easy accessibility of the system from virtually

anywhere in this world, which facilitates the scope of global or remote

administration possible. All the consistent transactions are facilitated by the

administrators only with proper authorization and authentication.

Cost Based:

If the physical system is established through a manual process. There is

much need of stationary that has to be managed and maintained as files, the

overall system once implemented as a intranet based web application notonly saves the time but also eliminates the latency that can exist within the

system, and saves the cost of stationary that is an unforeseen overhead

within the system.

The base administrative staff at the level of the strategic decision-making is

greatly relieved for the extensive data search. The administrators are greatly

benefited by this system, as they need not collect all that information that is

accessible by only selects that information which is more important for them.

The administrative standards of the system become more economical as

there is no need of stationary exchange within the organization. As the

information governed upon the system maintains statistics related to


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information that is collected, the overall system can be used for forecasting

analysis in the research process.

In the manual process of the Web Based Accommodation Upholding and

Maintenance System, the information search and storage needs extra

manpower assignment, which potentially costs the organization in the

perennial investment of funds for the sake of the salaries. The information

interrelations among different areas of the system should be handled

carefully else the latency upon the overall process of the system increases

leading to inconvenience.

SOFTWARE REQUIREMENT SPECIFICATION

REQUIREMENT SPECIFICATION:

The software, Web Based Accommodation upholding Maintenance System,

which is designed for administrating & automating all the major activities

that are carried out by the Tourists and the Accommodation providing outlets

as specific requirements arise upon the system.

INTRODUCTION

Purpose: The main purpose for preparing this document is to give a general

insight into the analysis and requirements of the existing system or situation

and for determining the operating characteristics of the system.

Scope: This Document plays a vital role in the development life cycle (SDLC)

As it describes the complete requirement of the system. It is meant for use

by the developers and will be the basic during testing phase. Any changes

made to the requirements in the future will have to go through formal

change approval process.


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Developers Responsibilities Overview:

The developer is responsible for:

Developing the system, which meets the SRS and solving all the

requirements of the system?

Demonstrating the system and installing the system at client's location after

the acceptance testing is successful.

Submitting the required user manual describing the system interfaces to

work on it and also the documents of the system.

Conducting any user training that might be needed for using the system.

Maintaining the system for a period of one year after installation.

Functional Requirements:

Inputs: The major inputs for Integration of Web based Accommodation

Upholding Maintenance System can be categorized module -wise. Basically all

the information is managed by the software and in order to access the

information one has to produce one's identity by entering the user-id and

password. Every user has their own domain of access beyond which theaccess is dynamically refrained rather denied.

Output: The major outputs of the system are tables and reports. Tables are

created dynamically to meet the requirements on demand. Reports, as it is

obvious, carry the gist of the whole information that flows across the

institution.

This application must be able to produce output at different modules for

different inputs.


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Performance Requirements:

Performance is measured in terms of reports generated weekly and monthly.

Intended Audience And Reading Suggestions

The document is prepared keeping is view of the academic constructs of my

Bachelors Degree / Masters Degree from university as partial fulfillment of

my academic purpose the document specifies the general procedure that that

has been followed by me, while the system was studied and developed. The

general document was provided by the industry as a reference guide to

understand my responsibilities in developing the system, with respect to the

requirements that have been pin pointed to get the exact structure of the

system as stated by the actual client.

The system as stated by my project leader the actual standards of the

specification were desired by conducting a series of interviews and

questionnaires. The collected information was organized to form the

specification document and then was modeled to suite the standards of the

system as intended.

Document Conventions:

The overall documents for this project use the recognized modeling

standards at the software industries level.

ER-Modeling to concentrate on the relational states existing upon the system

with respect to Cardinality.

The Physical dispense, which state the overall data search for the relational

key whereas a transactions is implemented on the wear entities.

Unified modeling language concepts to give a generalized blue print for the

overall system.

The standards of flow charts at the required states that are the functionality

of the operations need more concentration.


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Scope of The Development Project:

Database Tier: The concentration is applied by adopting the Oracle 9i

Enterprise versions. SQL is taken as the standard query language. The

overall business rules are designed by using the power of PL/SQL

components like stored procedures stored functions and database triggers.

User Tier: The use interface is developed is a browses specific environment

to have distributed architecture. The components are designed using HTML

standards and Java server pages power the dynamic of the page design.

Data Base Connectivity Tier: The communication architecture is designed

by concentrated on the standards of servlets and JSPs. The database

connectivity is established using the Java Database connectivity.


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Chapter 4


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Software RequirementSpecification


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Required Hardware

Pentium IV Processor.

128 MB RAM.

20GB Hard Disk space.Ethernet card with an Internet and Internet zone.

Required Software

Windows 2000 Professional operating system.Internet explorer 5.0 and Netscape navigator.

Oracle 8i.Servlets

JSP

TCP/IP Protocol suite.


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Chapter 5


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ModulesDescription


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Number of Modules:

Accommodation Information Module

Units Information Module.

Bookings Information Module.

Guests Information Module.

Facilities Information Module.

ACCOMMODATION INFORMATION: This module maintains all the details of

the Accommodation location that are available and the units that are

available under each location along with their reference unit types.

UNITS INFORMATION: This module maintains the information regarding allthe units that are registered as per specifications and their reference unit

types. The module also takes care of the system from the unit facilities and

reference unit facilities that are available.

BOOKING MODULE: This module maintains the information of all the booking

of the units, as pet the guest requirements, it inteplater itself with the units

station database and the specific registered guest who have raised the

demand upon the booking.

GUEST MODULE: This module maintains the overall activities through which a

guest is uniquely registered is the domain the module interpreter with the

specific gender status and also centrally sets with interpretation through

booking and registry to unit status.

FACILITIES MODULE: This module maintains the overall activities in the

facilities that are available are provided fn all or some of the specified units.

This module helps in registering the reference unit facilities that may creep in

into the system from time to time.


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NUMBER OF VIEWS:

Administrative View

Guest View

Administrative View

This view is designed for interacting with the absolute Meta Data, which

becomes the ultimate repository to maintain the consistency.

This view is accessible only to registered administrators who are recognized

by the Watershed Development central Administration Department.

This Module takes care of the responsibility of the major Table management

for

Data Insertion

Data Deletion

Data Updating

Data Selection

All the activities are validated and authenticated to proper profile to avoid un

authorized access.

Guest View: In this view the guest can view complete details of available

accommodation list information.


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Chapter 6


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AnalysisReport


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SOFTWARE REQUIREMENT SPECIFICATION

REQUIREMENT SPECIFICATION:

INTRODUCTION

Purpose: The main purpose for preparing this document is to give a general

insight into the analysis and requirements of the existing system or situation

and for determining the operating characteristics of the system.

Scope: This Document plays a vital role in the development life cycle (SDLC)

as it describes the complete requirement of the system. It is meant for use

by the developers and will be the basic during testing phase. Any changes

made to the requirements in the future will have to go through formal

change approval process.

Developers Responsibilities Overview:

The developer is responsible for:

1) Developing the system, which meets the SRS and solving all the

requirements of the system?

2) Demonstrating the system and installing the system at client'slocation after the acceptance testing is successful.

3) Submitting the required user manual describing the system

interfaces to work on it and also the documents of the system.

4) Conducting any user training that might be needed for using the

system.

5) Maintaining the system for a period of one year after installation.

Functional Requirements:

Inputs: The major inputs for Web Based Accommodation can be categorized

module-wise. Basically all the information is managed by the software and in


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order to access the information one has to produce one's identity by entering

the user-id and password. Every user has their own domain of access beyond

which the access is dynamically refrained rather denied.

Output: The major outputs of the system are tables and reports. Tables are

created dynamically to meet the requirements on demand. Reports, as it is

obvious, carry the gist of the whole information that flows across the

institution. This application must be able to produce output at different

modules for different inputs.

Performance Requirements:

Performance is measured in terms of reports generated weekly and monthly.

Intended Audience And Reading Suggestions

The document is prepared keeping is view of the academic constructs of my

Bachelors Degree / Masters Degree from university as partial fulfillment of

my academic purpose the document specifies the general procedure that that

has been followed by me, while the system was studied and developed. The

general document was provided by the industry as a reference guide to

understand my responsibilities in developing the system, with respect to therequirements that have been pin pointed to get the exact structure of the

system as stated by the actual client.

The system as stated by my project leader the actual standards of the

specification were desired by conducting a series of interviews and

questionnaires. The collected information was organized to form the

specification document and then was modeled to suite the standards of the

system as intended.

Document Conventions:

The overall documents for this project use the recognized modeling

standards at the software industries level.


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ER-Modeling to concentrate on the relational states existing

upon the system with respect to Cardinality.

The Physical dispense, which state the overall data search for

the relational key whereas a transactions is implemented on the

wear entities.

Unified modeling language concepts to give a generalized blue

print for the overall system.

The standards of flow charts at the required states that are the

functionality of the operations need more concentration.

Scope of The Development Project:

Database Tier: The concentration is applied by adopting the Oracle 8i

Enterprise versions. SQL is taken as the standard query language. The

overall business rules are designed by using the power of PL/SQL

components like stored procedures stored functions and database triggers.

User Tier: The use interface is developed is a browses specific environment

to have distributed architecture. The components are designed using HTML

standards and Java server pages power the dynamic of the page design.

Data Base Connectivity Tier: The communication architecture is designed

by concentrated on the standards of servlets and JSPs. The database

connectivity is established using the Java Database connectivity.

Role Of Oracle In Database

ORACLE 8i is one of the many database services that plug into a client /

server model. It works efficiently to manage resources, a database

information, among the multiple clients requesting & sending.

Structured Query Language (SQL)

SQL is an inter-active language used to query the database and access data

in database. SQL has the following features:


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1. It is a unified language.

2. It is a common language for relational database

3. It is a non-procedural language.


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Introduction To Oracle

ORACLE is a comprehensive operating environment that packs the power of a

mainframe system into user microcomputer. It provides a set of functional

programs that user can use as tools to build structures and perform tasks.Because application developed on oracle are completely portable to

environment and then move it into a multi user platform. Users do not have

to be an expert to appreciate ORACLE, but the better user understands the

programmer, the more productivity and creativity you will use the tools it

provides.

What is a Relational Database Management System?

A relational database management system (RDBMS) can perform a widearray of tasks. It acts as a transparent interface between the physical

storage and a logical presentation of data. It provides a set of more or less

flexible and sophisticates tools for handling information. User can use this

tool to:

Define a database

Query the database

Add, edit and delete data

Modify the structure of database

Secure data from public access

Communicate within the networks

Export and Import data

Because it gives so much control over data, a relational DBMS can also save

as the foundation for products that generate application and extract data.

A Database Management system may be called fully relational if it supports:

Relational Databases and

A language that is at least as powerful as the

relational algebra


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Dr. E.F.CODDSS RULES

E.F.Codd specified a set of rules that an RDBMS has to do following

12 rules

Information rule: All information in a relational database including

table names, column names, and domain names is represented explicitly

by values in tables. With this design speed and productivity will be

improved.

1. Guaranteed access rule: using a combination of table name, a

primary key value and a column name can access Every piece of data

in a relational database. With this productivity is improved since thereis no need to resort to using physical pointers of address and provides

data independence.

2. Systematic treatment of null values: The RDBMS distinguishes

between blanks nulls in records and handles such values in consistent

manner that produces correct answers on comparison and calculations.

With these users can distinguish results of queries/operations that

involve nulls, zeroes and blanks.

3. Active on-line catalog based on the relational model: The

description of a database and its contents are database tables and

therefore can be queried on-line via the database language. With this

the DBAs productivity is improved since the changes are common in

catalog to all tables for all queries and reports.

4. Comprehensive data sub-language rule: An RDBMS language

supports definitions of tables/views. Query and update data, integrity

constraints, authorizations, definitions of transactions. With this user

productivity is improved since there is a single approach for all

database operations.

5. View updating rule: Any view that is theoretically updateable can be

updated using RDBMS. With this data consistency is ensured since


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changes in the underlying tables are transmitted to the view their

support.

6. High-level insert, update and delete: The RDBMS supports

insertion, updating deletion at al table level. With this the performance

is improved by optimizing the path for execution.

7. Physical data independence: The execution of adhoc requests and

application programs are not affected by the changes in the physical

data access methods. With this DBA can make changes in application

programs or adhoc requests.

8. Logical data independence: Logical changes in tables and views do

not require changes in the application programs or in the format of

adhoc requests. With this databases can change and grow withoutchanges in applications.

9. Integrity independence: Since constraints are stored in system

catalog, they can be changed without changing application program.

With this maintenance costs are reduced since only system catalog

need to be changed.

10.Distribution independence: Application programs and adhoc

requests are not affected by changes in the distribution of physical

data. With this system reliability will be improved since applicationprograms will work even if the programs and dare are shifted.

11.Non-Subversion rule: If the RDBMS has languages that access a

record of a time it cannot be used to bypass integrity. With this data

integrity is achieved since the system catalog is musts

a. Code defined a relationally complete set of operations taking

one or more relation as their operands. The operators are two

groups: the traditional set of operators union, intersection,

difference and Cartesian product and the special operators

selection, projection, join and division.

b. A fully relational DBMS has to support the above operations.


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The Oracle Environment

ORACLE is modular system that consists of the ORACLE database and

several functional programs. ORACLE tools had four kinds of

works:

Database management

Data access and manipulations

Programming

Connectivity

Database Management Tools

This is usually (known as RDBMS by ORACLE) includes the core programs of

Oracles database management system, the ORACLE database with its

associated tables and views, which are stored in the Oracles data dictionary

and a group of helpful activities. The data dictionary sores information

related to every facet of database system. User names, user access rights,

table storage information and auditing data for the disaster recovery are all

stored in the data dictionary.

Data Access and Manipulations

All of Oracles data access and manipulation tools are firmly based on ANSI

standard SQL. In Oracle, the tools that a user will use to access and

manipulate data, has well as to design or use applications. Each provides

separate point of entry and unique speech to the Oracle system. SQL*PLUSallows direct access to database with SQL FORMS offer a user-friendly way to

create and use forms. SQL*REPORT writer lets you to creates formatted

output SQL*MENU provides a way for you to integrate your application

menus.


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Oracle Supports Applications Development

SQL*FORMS is an excellent user-friendly tool for quickly creating forms. User

can start with extremely simple default forms or use the full screen painting

function to create detailed screens foe accessing and updating multiple tables

and for controlling and editing the data as is entered. In SQL FORMS,

ORACLE provides unique control devices called TRIGGERS to influence user

action on a field before, during and after date input. Those triggers can

execute SQL commands, native SQL FORMS commands, or external

procedural language sub routines from with a form. These forms are an

advanced fourth-generation tool that wills adapt to your requirementsextremely well. With SQL*MENU you can link all of theforms. Programs and

queries are easily maintained with the secured menu structures. Oracle Uses

The SQL Command Set With SQL * Menu you can like all forms, programs

and queries in easily maintained secure structures.


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Oracle provides a SQL command set that is close to the ANSI standard

ORACLE has added extensive report-formatting commands to

extend the direct SQL language our capabilities and to delay the

needs for alternative report formatting techniques. Statistical,

Arithmetic string date/time functions are also included.

ORACLE has with limitation. The Single-user does not include all of the tools

available on the hardware platforms. Also. ORACLE is relatively

expensive and more complex than more single user, PC-basis

database managers. ORACLE delivers a comprehensive package

that allows for unlimited growth.

Oracle Gives You Security and Control ORACLE has several features that

ensure the integrity of user database. I f an interruption occurs in

processing, a rollback can rest the database to a point before the

disaster. If a restore is necessary, ORACLE has a roll forward

command for creating a database to its most recent save point.

Oracle provides users with several functions for serving data.

Grant and Revoke commands limited access to information down

to the row and column levels. Views are valuable future for limiting

access to the primary tables in the database.

Oracle Performs Completive


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ORACLE has been constantly improved to perform competitively on the

largest database because RDBMS has been hampered by a

repetition for slow access time. ORACLE had to prove itself

continuously and so the unique feature of clustering techniques for

storing data on the disk or another performance gained. Additional

functions help control complex database installations. The active

data dictionary, which automatically update and logs modification

to the database provide documentation data off loading form the

modification process. Finally, ORACLE stores the DBMS kernel in

extended memory, so more main memory is available for the

application.


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Programming Tools

One of the most important categories of tools available from oracle is its

series of programming interface. This precompiled software

provides a convenient and easy to use method of incorporatingORACLE SQL statement in high level programming language.

Current oracle can interface with COBOL and C.

Connective Tools

Connectivity tools make oracle available to network and to other database

managers. SQL * Star is group of products including SQL *NET

and SQL * connect that allows user to use stores on remote

machines. A micro based version of oracle called network station

oracle, user may SQL * NET, instead of oracle RDBMS. SQL *

Connection does the translating interactively without any

modification or translations.

Fourth Generation Languages

The fourth generation languages were created to overcome the problem of

third generation languages, and these 4GLs are generally referred

to as high productivity languages.

Objectives Of Fourth Generation Languages

To speed up the application building process

To make the application building process

To minimize the debugging problems

To generate bug free code from high level of expressions of

requirements.

To make languages easy to use and understand

All these make the end users solve their own problems and pit computers to

work.

Characteristics of Fourth Generation Languages

Simple Query facilities/ language


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Complex query and updating language

Report generators

Graphic languages

Decision support languages

Application generations

Specification language

Very high level language

Parameterized application language

Application language

Properties of Fourth Generation Languages

Easy to use

Employees a database management system directly

Requires significantly fewer instructions than third

generation language

Intelligent default assumptions make abort what the use

wants possible

Easy to understand and maintain

Enforces and encourages structured code

Subset can learnt not by non-technical users in a short

period


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Chapter

7


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Client ServerTechnologies


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Client Server

Over view:

With the varied topic in existence in the fields of computers, Client Server is

one, which has generated more heat than light, and also more hype thanreality. This technology has acquired a certain critical mass attention with its

dedication conferences and magazines. Major computer vendors such as IBM

and DEC; have declared that Client Servers is their main future market. A

survey of DBMS magazine reveled that 76% of its readers were actively

looking at the client server solution. The growth in the client server

development tools from $200 million in 1992 to more than $1.2 billion in

1996.

Client server implementations are complex but the underlying concept is

simple and powerful. A client is an application running with local resources

but able to request the database and relate the services from separate

remote server. The software mediating this client server interaction is often

referred to as MIDDLEWARE.

The typical client either a PC or a Work Station connected through a network

to a more powerful PC, Workstation, Midrange or Main Frames server usually

capable of handling request from more than one client. However, with someconfiguration server may also act as client. A server may need to access

other server in order to process the original client request.

The key client server idea is that client as user is essentially insulated from

the physical location and formats of the data needs for their application. With

the proper middleware, a client input from or report can transparently access

and manipulate both local database on the client machine and remote

databases on one or more servers. An added bonus is the client server opens

the door to multi-vendor database access indulging heterogeneous table

joins.


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What is a Client Server

Two prominent systems in existence are client server and file server systems.

It is essential to distinguish between client servers and file server systems.

Both provide shared network access to data but the comparison dens there!

The file server simply provides a remote disk drive that can be accessed by

LAN applications on a file-by-file basis. The clientserver offers full relational

database services such as SQL-Access, Record modifying, Insert, Delete with

full relational integrity backup/ restore performance for high volume of

transactions, etc. the client server middleware provides a flexible interfacebetween client and server, who does what, when and to whom.

Why Client Server

Client server has evolved to solve a problem that has been around since the

earliest days of computing: how best to distribute your computing, data

generation and data storage resources in order to obtain efficient, costeffective departmental an enterprise wide data processing. During mainframe

era choices were quite limited. A central machine housed both the CPU and

DATA (cards, tapes, drums and later disks). Access to these resources was

initially confined to batched runs that produced departmental reports at the

appropriate intervals. A strong central information service department ruled

the corporation. The role of the rest of the corporation limited to requesting

new or more frequent reports and to provide hand written forms from which

the central data banks were created and updated. The earliest client serversolutions therefore could best be characterized as SLAVE-MASTER.


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Time-sharing changed the picture. Remote terminal could view and even

change the central data, subject to access permissions. And, as the

central data banks evolved in to sophisticated relational database

with non-programmer query languages, online users could formulate

adhoc queries and produce local reports with out adding to the MIS

applications software backlog. However remote access was through

dumb terminals, and the client server remained subordinate to the

Slave\Master.

Front end or User Interface Design

The entire user interface is planned to be developed in browser specific

environment with a touch of Intranet-Based Architecture for achieving the

Distributed Concept.

The browser specific components are designed by using the HTML standards,

and the dynamism of the designed by concentrating on the constructs of the

Java Server Pages.

Communication or Database Connectivity Tier

The Communication architecture is designed by concentrating on the

Standards of Servlets and Enterprise Java Beans. The database connectivity

is established by using the Java Data Base Connectivity.

The standards of three-tire architecture are given major concentration to

keep the standards of higher cohesion and limited coupling for effectiveness

of the operations.

Features of The Language Used

In my project, I have chosen Java language for developing the code.

About Java

Initially the language was called as oak but it was renamed as Java in

1995. The primary motivation of this language was the need for a platform-


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independent (i.e., architecture neutral) language that could be used to create

software to be embedded in various consumer electronic devices.

Java is a programmers language.

Java is cohesive and consistent.

Except for those constraints imposed by the Internet

environment, Java gives the programmer, full control.

Finally, Java is to Internet programming where C was to

system programming.

Importance of Java to the Internet

Java has had a profound effect on the Internet. This is because; Java

expands the Universe of objects that can move about freely in Cyberspace.

In a network, two categories of objects are transmitted between the Server

and the Personal computer. They are: Passive information and Dynamic

active programs. The Dynamic, Self-executing programs cause serious

problems in the areas of Security and probability. But, Java addresses those

concerns and by doing so, has opened the door to an exciting new form of

program called the Applet.

Java can be used to create two types of programs

Applications and Applets: An application is a program that runs on our

Computer under the operating system of that computer. It is more or less

like one creating using C or C++. Javas ability to create Applets makes it

important. An Applet is an application designed to be transmitted over the

Internet and executed by a Java compatible web browser. An applet is

actually a tiny Java program, dynamically downloaded across the network,


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just like an image. But the difference is, it is an intelligent program, not just

a media file. It can react to the user input and dynamically change.

Features Of Java Security

Every time you that you download a normal program, you are risking aviral infection. Prior to Java, most users did not download executable

programs frequently, and those who did scanned them for viruses prior to

execution. Most users still worried about the possibility of infecting their

systems with a virus. In addition, another type of malicious program exists

that must be guarded against. This type of program can gather private

information, such as credit card numbers, bank account balances, and

passwords. Java answers both these concerns by providing a firewall

between a network application and your computer.

When you use a Java-compatible Web browser, you can safely download Java

applets without fear of virus infection or malicious intent.

Portability

For programs to be dynamically downloaded to all the various types of

platforms connected to the Internet, some means of generating portable

executable code is needed .As you will see, the same mechanism that helps

ensure security also helps create portability. Indeed, Javas solution to these

two problems is both elegant and efficient.

The Byte code

The key that allows the Java to solve the security and portability problems is

that the output of Java compiler is Byte code. Byte code is a highly optimized

set of instructions designed to be executed by the Java run-time system,

which is called the Java Virtual Machine (JVM). That is, in its standard form,

the JVM is an interpreter for byte code.

Translating a Java program into byte code helps makes it much easier to run

a program in a wide variety of environments. The reason is, once the run-

time package exists for a given system, any Java program can run on it.


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Although Java was designed for interpretation, there is technically nothing

about Java that prevents on-the-fly compilation of byte code into native

code. Sun has just completed its Just In Time (JIT) compiler for byte code.

When the JIT compiler is a part of JVM, it compiles byte code into executable

code in real time, on a piece-by-piece, demand basis. It is not possible to

compile an entire Java program into executable code all at once, because

Java performs various run-time checks that can be done only at run time.

The JIT compiles code, as it is needed, during execution.

Java Virtual Machine (JVM)

Beyond the language, there is the Java virtual machine. The Java virtual

machine is an important element of the Java technology. The virtual machine

can be embedded within a web browser or an operating system. Once a piece

of Java code is loaded onto a machine, it is verified. As part of the loading

process, a class loader is invoked and does byte code verification makes sure

that the code thats has been generated by the compiler will not corrupt the

machine that its loaded on. Byte code verification takes place at the end of

the compilation process to make sure that is all accurate and correct. So byte

code verification is integral to the compiling and executing of Java code.


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Overall Description

Picture showing the development process of JAVA Program

Java programming uses to produce byte codes and executes them. The first

box indicates that the Java source code is located in a. Java file that is

processed with a Java compiler called javac. The Java compiler produces a

file called a. class file, which contains the byte code. The. Class file is then

loaded across the network or loaded locally on your machine into the

execution environment is the Java virtual machine, which interprets and

executes the byte code.

Java Architecture

Java architecture provides a portable, robust, high performing environment

for development. Java provides portability by compiling the byte codes for

the Java Virtual Machine, which is then interpreted on each platform by the

run-time environment. Java is a dynamic system, able to load code when

needed from a machine in the same room or across the planet.

Compilation of code

When you compile the code, the Java compiler creates machine code (called

byte code) for a hypothetical machine called Java Virtual Machine (JVM). The

JVM is supposed to execute the byte code. The JVM is created for overcoming

the issue of portability. The code is written and compiled for one machine

and interpreted on all machines. This machine is called Java Virtual Machine.

Java Source Java byte code Java VM

Java .Class


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Compiling and interpreting Java Source Code

During run-time the Java interpreter tricks the byte code file into thinking

that it is running on a Java Virtual Machine. In reality this could be a Intel

Pentium Windows 95 or SunSARC station running Solaris or Apple Macintosh

running system and all could receive code from any computer through

Internet and run the Applets.

Simple

Java was designed to be easy for the Professional programmer to learn and

to use effectively. If you are an experienced C++ programmer, learning Java

will be even easier. Because Java inherits the C/C++ syntax and many of the

object oriented features of C++. Most of the confusing concepts from C++

are either left out of Java or implemented in a cleaner, more approachable

manner. In Java there are a small number of clearly defined ways to

accomplish a given task.

SourceCode....

..

PC Compiler

MacintoshCompiler

SPARC

Compiler

Java

Byte code

(PlatformIndependent)

JavaInterpreter(PC)

JavaInterpreter(Macintosh)JavaInterpreter(Spare)


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Object-Oriented

Java was not designed to be source-code compatible with any other

language. This allowed the Java team the freedom to design with a blank

slate. One outcome of this was a clean usable, pragmatic approach toobjects. The object model in Java is simple and easy to extend, while simple

types, such as integers, are kept as high-performance non-objects.

Robust

The multi-platform environment of the Web places extraordinary demands on

a program, because the program must execute reliably in a variety of

systems. The ability to create robust programs was given a high priority in

the design of Java. Java is strictly typed language; it checks your code atcompile time and run time.

Java virtually eliminates the problems of memory management and

deallocation, which is completely automatic. In a well-written Java program,

all run time errors can and should be managed by your program.


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Servlets, JSP, JDBC &HTML Technologies


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MySQL

The MySQL(TM) software delivers a very fast, multi-threaded, multi-user,

and robust SQL (Structured Query Language) database server. MySQL

Server is intended for mission-critical, heavy-load production systems aswell as for embedding into mass-deployed software. MySQL is a

trademark ofMySQL AB.

What Is MySQL?

MySQL, the most popular Open Source SQL database, is developed,

distributed, and supported by MySQL AB. MySQL AB is a commercial

company, founded by the MySQL developers, that builds its businessproviding services around the MySQL database.

MySQL is a database management system.

A database is a structured collection of data. It may be anything from a

simple shopping list to a picture gallery or the vast amounts of

information in a corporate network. To add, access, and process data

stored in a computer database, you need a database management system

such as MySQL Server. Since computers are very good at handling largeamounts of data, database management systems play a central role in

computing, as stand-alone utilities or as parts of other applications.

MySQL is a relational database management system.

A relational database stores data in separate tables rather than putting all

the data in one big storeroom. This adds speed and flexibility. The SQL

part of ``MySQL'' stands for ``Structured Query Language''. SQL is the most

common standardised language used to access databases and is defined

by the ANSI/ISO SQL Standard.(The SQL standard has been evolving

since 1986 and several versions exist. In this manual, ''SQL-92'' refers to

the standard released in 1992, ''SQL-99'' refers to the standard released in

1999, and ''SQL:2003'' refers to the version of the standard that is
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expected to be released in mid-2003.We use the term ''the SQL standard''

to mean the current version of the SQL Standard at any time.)

MySQL software is Open Source.

Open Source means that it is possible for anyone to use and modify the

software. Anybody can download the MySQL software from the Internet

and use it without paying anything. If you wish, you may study the source

code and change it to suit your needs. The MySQL software uses the GPL

(GNU General Public License), http://www.gnu.org/licenses/, to define what

you may and may not do with the software in different situations. If you

feel uncomfortable with the GPL or need to embed MySQL code into a

commercial application you can buy a commercially licensed version from

us.

Why use the MySQL Database Server?

The MySQL Database Server is very fast, reliable, and easy to use. If that is

what you are looking for, you should give it a try. MySQL Server also has a

practical set of features developed in close cooperation with our users.

You can find a performance comparison of MySQL Server with other

database managers on our benchmark page. MySQL Server was originallydeveloped to handle large databases much faster than existing solutions

and has been successfully used in highly demanding production

environments for several years. Though under constant development,

MySQL Server today offers a rich and useful set of functions. Its

connectivity, speed, and security make MySQL Server highly suited for

accessing databases on the Internet.

The technical features of MySQL Server:

The MySQL Database Software is a client/server system that consists of a

multi-threaded SQL server that supports different backends, several

different client programs and libraries, administrative tools, and a wide

range of programming interfaces (APIs). We also provide MySQL Server as
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a multi-threaded library which you can link into your application to get a

smaller, faster, easier-to-manage product.

There is a large amount of contributed MySQL software available.

It is very likely that you will find that your favorite application or language

already supports the MySQL Database Server.

The official way to pronounce MySQL is ``My Ess Que Ell'' (not ``my

sequel''),

History of MySQL:

We started out with the intention of using mSQL to connect to our tables

using our own fast low-level (ISAM) routines. However, after some testingwe came to the conclusion that mSQL was not fast enough nor flexible

enough for our needs. This resulted in a new SQL interface to our

database but with almost the same API interface as mySQL. This API was

chosen to ease porting of third-party code.

The derivation of the name MySQL is not clear. Our base directory and a

large number of our libraries and tools have had the prefix ``my'' for well

over 10 years. However, co-founder Monty Wideness daughter (someyears younger) is also named My. Which of the two gave its name to

MySQL is still a mystery, even for us.

The name of the MySQL Dolphin (our logo) is Sakila. Sakila was chosen by

the founders of MySQL AB from a huge list of names suggested by users

in our "Name the Dolphin" contest. The winning name was submitted by

Ambrose Twebaze, an open source software developer from Swaziland,

Africa. According to Ambrose, the name Sakila has its roots in SiSwati,the local language of Swaziland. Sakila is also the name of a town in

Arusha, Tanzania, near Ambrose's country of origin, Uganda.
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The Main Features of MySQL:

The following list describes some of the important characteristics of the

MySQL Database Software.

Internals and Portability:

Written in C and C++. Tested with a broad range of different

compilers.

Works on many different platforms. on Operating Systems

Supported by MySQL.

Uses GNU Automake, Autoconf, and Libtool for portability.

APIs for C, C++, Eiffel, Java, Perl, PHP, Python, Ruby, and Tcl. Seesection 8 MySQL APIs.

Fully multi-threaded using kernel threads. This means it can easily

use multiple CPUs if available.

Transactional and non-transactional storage engines.

Very fast B-tree disk tables (MyISAM) with index compression.

Relatively easy to add another storage engine. This is useful if you

want to add an SQL interface to an in-house database.

A very fast thread-based memory allocation system.

Very fast joins using an optimised one-sweep multi-join.

In-memory hash tables which are used as temporary tables.

SQL functions are implemented through a highly optimised class

library and should be as fast as possible. Usually there isn't any

memory allocation at all after query initialisation.

The MySQL code gets tested with Purify (a commercial memory

leakage detector) as well as with Valgrind, a GPL tool(http://developer.kde.org/~sewardj/).

Available as client/server or embedded (linked) version.

Column Types:
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Many column types: signed/unsigned integers 1, 2, 3, 4, and

8 bytes long, FLOAT, DOUBLE, CHAR, VARCHAR, TEXT, BLOB,

DATE, TIME, DATETIME, TIMESTAMP, YEAR, SET, and ENUM

types. See section 6.2 Column Types.

Fixed-length and variable-length records.

Commands and Functions:

Full operator and function support in the SELECT and

WHERE clauses of queries. For example:

mysql> SELECT CONCAT(first_name, " ", last_name)

FROM tbl_name

WHERE income/dependents > 10000 AND age > 30;

Full support for SQL GROUP BY and ORDER BY clauses.

Support for group functions (COUNT(),

COUNT(DISTINCT ...), AVG(), STD(), SUM(), MAX(), MIN(),

and GROUP_CONCAT()).

Support for LEFT OUTER JOIN and RIGHT OUTER JOIN with

both standard SQL and ODBC syntax.

Support for aliases on tables and columns as required by

SQL-92.

DELETE, INSERT, REPLACE, and UPDATE return the number

of rows that were changed (affected). It is possible toreturn the number of rows matched instead by setting a

flag when connecting to the server.

The MySQL-specific SHOW command can be used to

retrieve information about databases, tables, and
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indexes. The EXPLAIN command can be used to determine

how the optimiser resolves a query.

Function names do not clash with table or column names.

For example, ABS is a valid column name. The only

restriction is that for a function call, no spaces are

allowed between the function name and the `(' that

follows it. See section 6.1.7 Is MySQL Picky About

Reserved Words?.

You can mix tables from different databases in the same

query (as of Version 3.22).

Security:

A privilege and password system that is very flexible and secure, and

allows host-based verification. Passwords are secure because all password

traffic is encrypted when you connect to a server.

Scalability and Limits:

Handles large databases. We use MySQL Server with databases that

contain 50 million records. We also know of users that use MySQL

Server with 60,000 tables and about 5,000,000,000 rows.

Up to 32 indexes per table are allowed. Each index may consist of 1

to 16 columns or parts of columns. The maximum index width is

500 bytes (this may be changed when compiling MySQL Server). An

index may use a prefix of a CHAR or VARCHAR field.

Connectivity:

Clients may connect to the MySQL server using TCP/IP

Sockets, Unix Sockets (Unix), or Named Pipes (NT).
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ODBC (Open-DataBase-Connectivity) support for Win32 (with

source). All ODBC 2.5 functions are supported, as are many

others. For example, you can use MS Access to connect to

your MySQL server. See section 8.2 MySQL ODBC Support.

Localisation:

The server can provide error messages to clients in

many languages. See section 4.6.2 Non-English Error

Messages.

Full support for several different character sets,

including ISO-8859-1 (Latin1), german, big5, ujis, and

more. For example, the Scandinavian characters '','' and '' are allowed in table and column names.

All data is saved in the chosen character set. All

comparisons for normal string columns are case-

insensitive.

Sorting is done according to the chosen character set

(the Swedish way by default). It is possible to change

this when the MySQL server is started. To see an

example of very advanced sorting, look at the Czech

sorting code. MySQL Server supports many different

character sets that can be specified at compile and

runtime.

Clients and Tools

Includes myisamchk, a very fast utility for table

checking,optimisation, and repair. All of the functionality of

myisamchk is also available through the SQL interface. See

section 4 Database Administration.

All MySQL programs can be invoked with the --help or -?

options to obtain online assistance.
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How Stable Is MySQL?

This section addresses the questions ``How stable is MySQL Server?'' and

``Can I depend on MySQL Server in this project?'' We will try to clarify

these issues and answer some important questions that concern manypotential users. The information in this section is based on data gathered

from the mailing list, which is very active in identifying problems as well

as reporting types of use.

Original code stems back from the early '80s, providing a stable code

base, and the ISAM table format remains backward-compatible. At TcX,

the predecessor ofMySQL AB, MySQL code has worked in projects since

mid-1996, without any problems. When the MySQL Database Softwarewas released to a wider public, our new users quickly found some pieces

of ``untested code''. Each new release since then has had fewer

portability problems (even though each new release has also had many

new features).

Each release of the MySQL Server has been usable. Problems have

occurred only when users try code from the ``gray zones.'' Naturally,

new users don't know what the gray zones are; this section thereforeattempts to document those areas that are currently known. The

descriptions mostly deal with Version 3.23 and 4.0 of MySQL Server. All

known and reported bugs are fixed in the latest version, with the

exception of those listed in the bugs section, which are things that are

design-related. See section 1.8.6 Known Errors and Design Deficiencies in

MySQL.

The MySQL Server design is multi-layered with independent modules.

Some of the newer modules are listed here with an indication of how well-

tested each of them is:
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How Big Can MySQL Tables Be?

MySQL Version 3.22 had a 4 GB (4 gigabyte) limit on table size. With the

MyISAM table type in MySQL Version 3.23, the maximum table size was

pushed up to 8 million terabytes (2 ^ 63 bytes).

Note, however, that operating systems have their own file-size limits.

Here are some examples:

Operating System File-Size Limit

Linux-Intel 32 bit 2 GB, 4GB or more, depends on Linux version

Linux-Alpha 8 TB (?)

Solaris 2.5.1 2 GB (possible 4GB with patch)

Solaris 2.6 4 GB (can be changed with flag)

Solaris 2.7 Intel 4 GB

Solaris 2.7 UltraSPARC 512 GB

SERVLETS

Introduction

The Java web server is JavaSoft's own web Server. The Java web server is

just a part of a larger framework, intended to provide you not just with a

web server, but also with tools. To build customized network servers for any

Internet or Intranet client/server system. Servlets are to a web server, how

applets are to the browser.

About Servlets

Servlets provide a Java-based solution used to address the problems

currently associated with doing server-side programming, including
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inextensible scripting solutions, platform-specific APIs, and incomplete

interfaces.

Servlets are objects that conform to a specific interface that can be plugged

into a Java-based server. Servlets are to the server-side what applets are to

the client-side - object byte codes that can be dynamically loaded off the net.

They differ from applets in that they are faceless objects (without graphics or

a GUI component). They serve as platform independent, dynamically

loadable, plugable helper byte code objects on the server side that can be

used to dynamically extend server-side functionality.

For example, an HTTP Servlets can be used to generate dynamic HTML

content. When you use Servlets to do dynamic content you get the following

advantages: Theyre faster and cleaner than CGI scripts

They use a standard API (the Servlets API)

They provide all the advantages of Java (run on a variety of

servers without needing to be rewritten).

Attractiveness of Servlets

There are many features of Servlets that make them easy and attractive to

use. These include:

Easily configured using the GUI-based Admin tool

Can be loaded and invoked from a local disk or remotely across

the network.

Can be linked together, or chained, so that one Servlets can call

another Servlets, or several Servlets in sequence.

Can be called dynamically from within HTML pages, using

server-side include tags.

Are secure - even when downloading across the network, the

Servlets security model and Servlets sandbox protect your

system from unfriendly behavior.


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Advantages of the Servlet API

One of the great advantages of the Servlet API is protocol independence. It

assumes nothing about:

The protocol being used to transmit on the net

How it is loaded

The server environment it will be running in

These qualities are important, because it allows the Servlet API to be

embedded in many different kinds of servers. There are other advantages to

the Servlet API as well. These include: Its extensible - you can inherit all your functionality from the base

classes made available to you.

Its simple, small, and easy to use.

Features of Servlets

Servlets are persistent. Servlet are loaded only by the web server

and can maintain services between requests.

Servlets are fast. Since Servlets only need to be loaded once, theyoffer much better performance over their CGI counterparts.

Servlets are platform independent.

Servlets are extensible. Java is a robust, object-oriented

programming language, which easily can be extended to suit your

needs

Servlets are secure.

Servlets can be used with a variety of clients.


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Loading Servlets

Servlets can be loaded from three places

From a directory that is on the CLASSPATH. The CLASSPATH of the

JavaWebServer includes service root/classes/ which is where the system

classes reside.

From the


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A client can invoke Servlets in the following ways:

The client can ask for a document that is served by the Servlet.

The client (browser) can invoke the Servlet directly using a URL, once

it has been mapped using the Servlet Aliases section of the admin GUI.

The Servlet can be invoked through server side include tags.

The Servlet can be invoked by placing it in the Servlets/ directory.

The Servlet can be invoked by using it in a filter chain.

JavaScript

JavaScript is a script-based programming language that was developed by

Netscape Communication Corporation. JavaScript was originally called Live

Script and renamed as JavaScript to indicate its relationship with Java.

JavaScript supports the development of both client and server components of

Web-based applications. On the client side, it can be used to write programs

that are executed by a Web browser within the context of a Web page. On

the server side, it can be used to write Web server programs that can

process information submitted by a Web browser and then updates the

browsers display accordingly

Even though JavaScript supports both client and server Web programming,

we prefer JavaScript at Client side programming since most of the browsers

supports it. JavaScript is almost as easy to learn as HTML, and JavaScript

statements can be included in HTML documents by enclosing the statements

between a pair of scripting tags

.. .

JavaScript statements

Here are a few things we can do with JavaScript:

Validate the contents of a form and make calculations.

Add scrolling or changing messages to the Browsers status line.

Animate images or rotate images that change when we move

the mouse over them.
http://opt/scribd/conversion/tmp/administration/servlet_alias.htmlhttp://opt/scribd/conversion/tmp/scratch15833/ssinclude.htmlhttp://opt/scribd/conversion/tmp/administration/servlet_alias.htmlhttp://opt/scribd/conversion/tmp/scratch15833/ssinclude.html


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Detect the browser in use and display different content for

different browsers.

Detect installed plug-ins and notify the user if a plug-in is

required.

We can do much more with JavaScript, including creating entire application.

JavaScript Vs Java

JavaScript and Java are entirely different languages. A few of the most

glaring differences are:

Java applets are generally displayed in a box within the web

document; JavaScript can affect any part of the Web document itself.

While JavaScript is best suited to simple applications and adding

interactive features to Web pages; Java can be used for incredibly

complex applications.

There are many other differences but the important thing to remember is

that JavaScript and Java are separate languages. They are both useful for

different things; in fact they can be used together to combine their

advantages.Advantages

JavaScript can be used for Sever-side and Client-side scripting.

It is more flexible than VBScript.

JavaScript is the default scripting languages at Client-side since

all the browsers supports it.

Hyper Text Markup Language

Hypertext Markup Language (HTML), the languages of the World Wide Web

(WWW), allows users to produces Web pages that include text, graphics and

pointer to other Web pages (Hyperlinks).


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HTML is not a programming language but it is an application of ISO Standard

8879, SGML (Standard Generalized Markup Language), but specialized to

hypertext and adapted to the Web. The idea behind Hypertext is that instead

of reading text in rigid linear structure, we can easily jump from one point to

another point. We can navigate through the information based on our

interest and preference. A markup language is simply a series of elements,

each delimited with special characters that define how text or other items

enclosed within the elements should be displayed. Hyperlinks are underlined

or emphasized works that load to other documents or some portions of the

same document.

HTML can be used to display any type of document on the host computer,

which can be geographically at a different location. It is a versatile language

and can be used on any platform or desktop.

HTML provides tags (special codes) to make the document look attractive.

HTML tags are not case-sensitive. Using graphics, fonts, different sizes, color,

etc., can enhance the presentation of the document. Anything that is not a

tag is part of the document itself.

Basic HTML Tags :

Specifies comments

. Creates hypertext links

. Formats text as bold

. Formats text in large font.

Contains all tags and text in the HTML

document

... Creates text


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Using JDBC, it is easy to send SQL statements to virtually any relational

database. One can write a single program using the JDBC API, and the

program will be able to send SQL statements to the appropriate database.

The combinations of Java and JDBC lets a programmer write it once and run

it anywhere.

What Does JDBC Do?

Simply put, JDBC makes it possible to do three things:

Establish a connection with a database

Send SQL statements

Process the results.

JDBC versus ODBC and other APIs

At this point, Microsoft's ODBC (Open Database Connectivity) API is that

probably the most widely used programming interface for accessing relational

databases. It offers the ability to connect to almost all databases on almost

all platforms.

So why not just use ODBC from Java? The answer is that you can use ODBC

from Java, but this is best done with the help of JDBC in the form of the

JDBC-ODBC Bridge, which we will cover shortly. The question now becomes

"Why do you need JDBC?" There are several answers to this question:

1. ODBC is not appropriate for direct use from Java because it uses a C

interface. Calls from Java to native C code have a number of

drawbacks in the security, implementation, robustness, and automatic

portability of applications.

2. A literal translation of the ODBC C API into a Java API would not be

desirable. For example, Java has no pointers, and ODBC makes

copious use of them, including the notoriously error-prone generic

pointer "void *". You can think of JDBC as ODBC translated into an

object-oriented interface that is natural for Java programmers.

3. ODBC is hard to learn. It mixes simple and advanced features

together, and it has complex options even for simple queries. JDBC, on


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the other hand, was designed to keep simple things simple while

allowing more advanced capabilities where required.

4. A Java API like JDBC is needed in order to enable a "pure Java"

solution. When ODBC is used, the ODBC driver manager and drivers

must be manually installed on every client machine. When the JDBC

driver is written completely in Java, however, JDBC code is

automatically installable, portable, and secure on all Java platforms

from network computers to mainframes.

Two-tier and Three-tier Models

The JDBC API supports both two-tier and three-tier models for database

access.

In the two-tier model, a Java applet or application talks directly to the

database. This requires a JDBC driver that can communicate with the

particular database management system being accessed. A user's SQL

statements are delivered to the database, and the results of those

statements are sent back to the user. The database may be located on

another machine to which the user is connected via a network. This is

referred to as a client/server configuration, with the user'

the system aims at the maintenance and

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