PROJECT REPORT
(January- May 2012)
³HOTEL INFORMATION SYSTEM´ A Capstone Project
Submitted by
Manish Kumar Registration No: 10801901 Programme: B.TECH CSE Section: K28E1
Under the Guidance of
Mrs.JaspreetKaur Lecturer CSE/IT School of Computer Science (K2) Lovely Professional University, Phagwara
PROJECT REPORT
(January- May 2012)
³HOTEL INFORMATION SYSTEM´ A Capstone Project
Submitted by
Manish Kumar Registration No: 10801901 Programme: B.TECH CSE Section: K28E1
Under the Guidance of
Mrs.JaspreetKaur Lecturer CSE/IT School of Computer Science (K2) Lovely Professional University, Phagwara
DECLARATION
I, Manish Kumar, student of B.Tech CSE under Department of Computer Science Engineering, School of Computer Science (K2) of Lovely Professional University, Punjab, hereby declare that all the information furnished in this capstone project report is based on my own intensive research and is genuine. This report does not, to the best of my knowledge, contain part of my work which has been submitted for the award of my degree either of this university or any other university without proper citation.
Date: March, 5, 2012
Signature Name of the student: Manish Kumar Registration No.: 10801901
ACKNOWLE DGEMENT
There are many persons to whom I owe thanks for their help, gracious advice, and suggestions during the various stages of this project. It is a combined effort of those who inspire and guide, of those who participate and o f those who support you when you stumble. Working on my project has been both challenging and interesting for me. The difficulties I met during this study were made into challenges to be met by those who guided my way through. With deep gratitude and immense pride, I would like to acknowledge the guidance and encouragement given to me by my mentor and guide Mrs. JASPREET KAUR. Her guidance has been inspiring and ever encouraging. Her encouragement has been there with me at every step that I have taken to fulfill the present work. I also thank my friends who so graciously gave their time for providing sample material throughout this project.
Manish Kumar
CERTIFICATE This is to certify that Manish Kumar bearing Registration no. 10801901 has completed his Capstone project titled, ³Hotel Information System´ under my guidance and supervision. To the best of my knowledge, the present work is the result of her original investigation and study. No part of the work has ever been submitted for any other degree at any University. The project is fit for submission and the partial fulfillment of the conditions for the award of Degree of Bachelor of Technology Computer Science Engineering.
Signature Name of the Research Supervisor: Mrs. JaspreetKaur Designation: Lecturer CSE/IT
School of Computer Engg.
School of Computer Science (K2)
Lovely Professional University Phagwara, Punjab.
Date: March, 5, 2012
INDEX 1. Organization Overview 2. Profile of the Problem 3. Existing System y
Introduction
y
Existing Software
y
What¶s new in the system to be developed
4. Problem Analysis y
Product definition
y
Feasibility
y
Project Plan
Analysis
5. Software Requirement Analysis y
Introduction
y
General
y
Specific Requirements
Description
6. Design y
System Design
y
Design Notations
y
Detailed Design
y
ER Diagrams
y
All keys & constraints
7. References
1.
Organization Overview
In the hotel information system contain the full information of the system and also contain the full information of the customer which want to for booking of the hotels. If any customer want the full information of the system then he/she search the hotel with the name of the hotel and their location. If customer want to book that hotel then he/she create his/her accou nt then he/she go for the procedure for the booking of the hotels. Hotel information system contain the full information of the customer with full detail and in the consistent order and it doesn¶t contain the redundancy in the database. Hotel information system provide the following categories Non-redundancy in the database Maintain the data properly Contain the full information of the system
Hotel information system provide the full categories for hotels and also for the customers. It provide the following facilities for the customer and for the hotels. Complete information of the hotels Complete information of the customer will stored in the dat abase Easily booking the hotel for t he customer If hotels department want the co mplete info of customer then they must use this
2. Problem Analysis Initial project decisions begin with development of a list of the transportation problems to be addressed by a project. The list of problems can then be transformed into a comprehensive need statement. It is critical for this statement to reflect the full range of public values identified through the public involvement process, and to legitimize all of the affected interests without appearing to favor [or promote] one particular solution. Initial project decisions begin with development of a list of the transportation problems to be addressed by a project.... The list of problems can then be transformed into a comprehensive need statement. It is critical for this statement to reflect the full range of public values identified through the public involvement process, and to legitimize all of the affected interests without appearing to favor [or promote] one particular solution The whole process of accessing information and booking the hotels are done manually till date. Processing the information of hotels, booking of hotels i.e. checking and booking of hotels take plenty of time, efforts and resources. As we already know that if any person want to go anywhere and on the spot he/she thinking that any hotel which can fulfill the requirement of the customer that must be here right now, what it is not so much simple. If that person first take the information of the hotel online and check all the facilities which is suited for the person then that person can¶t be in trouble. And the booking also is very difficult task when it can be done manually. If customer check all the information online and do the reservation online of the hotel then this difficulty doesn¶t be come, if it is not manually then. If all this works are manually then the following difficulty can be face by any person. Person can¶t get good hotels which can be suited for the person. User can¶t get the full information of the hotel manually. It also consume the time of the user. Booking procedure is also difficult manually then if user can¶t get the proper information
about the hotel. Application and data of various departments was not centralized .
Maintenance of the information about the various activity report like Daily Activity
Reports, Weekly Activity Reports and Monthly Activity Reports was manually handled.
3.
Existing System
3.1 Introduction:- Topic is ³Hotels Information System´ which is very unique topic for the
capstone project. The aim of this project is very simple that it provides the information about the hotels to customer. Customers can access the information about the hotels in a very legitimate way. There are various features of the HIS Search about any hostels are very easy with the locations. Customer create new account for the booking of the hotel which show all information of
the hotels and the payment detail and the price of the hotel. Customer also get the information about the confirmation of the booking for hotel. It also contain all information of the customer which can be entered by the customer in
the database.
HIS provide the consistency and non-redundant data in the database design phase. It also maintain the data properly and contain all the data in proper manner.
3.2 Existing system:- Existing system of the hotel information system does not contain all the
information of the hotels. In the present hotel information system doesn¶t provide the proper information and this system only provide the information about the hotels what it doesn¶t provide the booking module or the create new account of the customer. Then the present system can¶t contain the full information of the system. In the existing system has many deficiency which has following
Information are not maintain properly. Database are create manually which create the redundancy and inconsistency in the
database.
In the database has no unique key used which make it unique from other data. Maintenance of the information and database are not in proper manner and does¶t provide
any security to the database of the system.
3.3 New Developed In The System:- Main devolvement in the system has that maintain the
data in the database properly which doesn¶t contain the inconsistency, redundancy and in proper format of the data in database. And other development are following Customer login in account for the reservation of the hotel. Customer get confirmation of reservation of the hot el in their account. If any another customer want to create their account then he/she must create new account. All the database of the customer will be stored in the database properly and he/she access
full information of the hotel from the database.
4.
Product Analysis
4 .1
Product Definition:- In general, the product is defined as a "thing produced by labor or
effort´ or the "result of an act o r a process", and stems from the verb produce. In economics and commerce, products belong to a broader category of goods. The economic meaning of product was first used by po litical economist Adam Smith. In marketing, a product is anything that can be offered to a market that might satisfy a want or need. In retailing, products are called merchandise. In manufacturing, products are purchased as raw materials and sold as finished goods. Commodities are usually raw materials such as metals and agricultural products, but a commodity can also be anything widely available in the open market. In project management, products are the formal definition of the project deliverables that make up or contribute to delivering the objectives of the project. In insurance, the policies are considered products offered for sale by the insurance company that created the contract.
Product can be classified in the various forms: By properties. By use. By association. National and international product classification.
B
y properties:- Products can be classified as tangible or intangible. A tangible product is a
physical object that can be perceived by touch such as a house, automobile, computer, pencil. An intangible product is a product that can only be perceived indirectly such as an insurance po licy. B y
use:- In its online product catalog, retailer Sears, Roebuck and Company divides its products
into "departments", then presents products to potential shoppers according to function or brand. Each product has a Sears item-number and a manufacturer's model-number. Sears uses the departments and product groupings with the intention of helping customers browse products by function or brand within a traditional department-store structure. B y
association:- A product line is "a group of products that are closely related, either because
they function in a similar manner, are sold to the same customer groups, are marketed through the same types of outlets, or fall within given price ranges." Many businesses offer a range of product lines which may be unique to a single organization or may be common across the business's industry. In 2002 the US Census compiled revenue figures for the finance and insurance industry by various product lines such as "accident, health and medical insurance premiums" and "income from secured consumer loans". Within the insurance industry, product lines are indicated by the type of risk coverage, such as auto insurance, commercial insurance and life insurance. National and international product classifications:-
Various
classification systems for products
have been developed for economic statistical purposes. The NAFTA signatories are working on a system that classifies products called NAPCS as a companion to North American Industry Classification System (NAICS). The European Union uses a "Classification of Products by Activity" among other product classifications. The United Nations also classifies products for international economic activity reporting.
Product Description which used in Project
The important modules of the hotel information systems are search modules, register modules, booking modules. All the modules are very necessary for completion of the hotel information system. Search modules are mainly used for the searching the information about the hotels and contain complete information or data of the hotels. This module also provide the many another sub modules which make it very efficient. For example if any employee search about the hotels then information of the hotels will display with the type, brand, stars categories had shown in this modules. Another module is the booking module, which contain all the booking information guidance for the customer. If customer select any hotel and customer want booking of that hotels then booking module show all that information which is necessary for the booking. Booking module first show for the customer that if customer has already has their account then he/she will go for booking of hotels if the he/she has no account then first register and contain their account and then for booking process. Then register module will be connected with booking module which conation the full information of the customer. Search module contain the all the information about the hotel with all the information of the hotel and information of the will displayed with t heir type, stars and their brand name. Register module contain the personal and the educational information of the customer and provide an account for the customer for the booking for hotel. Booking module is only accessed if customer has their account then customer will access it. Customer fill all the information which can be given in the booking form then the booking of that customer will be confirmed.
4
.2 Feasibility Analysis:- Feasibility studies aim to objectively and rationally uncover the
strengths and weaknesses of the existing business or proposed venture, opportunities and threats as presented by the environment, the resources required to carry through, and ultimately the prospects for success. In its simplest term, the two criteria to judge feasibility are cost required and value to be attained. As such, a well-designed feasibility study should provide a historical background of the business or project, description of the product or service, accounting statements, details of the operations and management, marketing research and policies, financial data, legal requirements and tax obligations.
Generally,
feasibility studies precede technical
development and project implementation. Five factors of feasibility analysis: Technology and system feasibility Economic feasibility Legal feasibility Operational feasibility Operational feasibility
Technology and system feasibility:- The assessment is based on an outline design of system
requirements in terms of Input, Processes, Output, Fields, Programs, and Procedures. This can be quantified in terms of volumes of data, trends, frequency of updating, etc. in order to estimate whether the new system will perform adequately or not. Technological feasibility is carried out to determine whether the company has the capability, in terms of software, hardware, personnel and expertise, to handle the completion of the project. At this level, the concern is whether the proposal is both technically and legally feasible. Economic feasibility:- Economic analysis is the most frequently used method for evaluating the
effectiveness of a new system. More commonly known as cost/benefit analysis, the procedure is to determine the benefits and savings that are expected from a candidate system and compare them with costs. If benefits outweigh costs, then the decision is made to design and implement the system. An entrepreneur must accurately weigh the cost versus benefits before taking an action.
Cost-based study: It is important to identify cost and benefit factors, which can be categorized as follows: Development costs Operating costs. Time-based
study: This is an analysis of the time required to achieve a return on investments.
The future value of a project is also a factor. Legal
feasibility:- Determines whether the proposed system conflicts with legal requirements,
e.g. a data processing system must comply with the local Data Protection Acts. Operational feasibility:- Operational feasibility is a measure of how well a proposed system
solves the problems, and takes advantage of the opportunities identified during scope definition and how it satisfies the requirements identified in the requirements analysis phase of system development. Schedule feasibility:- A project will fail if it takes too long to be completed before it is useful.
Typically this means estimating how long the system will take to develop, and if it can be completed in a given time period using some methods like payback period. Schedule feasibility is a measure of how reasonable the project timetable is.
4 .3
Project Plan:- Project planning of the Hotel information System contain search module
which contain the information of the hotels. When information of the hotels are found with the name of location then the table which contain all location in the database, then the connectivity of that table and search module are unique. Booking module and register module which can connected with each other and also connected with the database which mostly contain all the information of customer e.g. name of the customer, phone no., age, educational information etc. There are many tables in database which present all the information of all the data which can be contained by the software. Then planning of project is based on the SDLC(System Development Life Cycle).
SDLC carefully lays out the necessary stages in order to create a perfect software. Developers realized that building a software is not all about answering the need but exceeding them. SDLC is now observed by different software engineers each of them following a specific model that works well with their talent and available resources. Each model suggests different stages in software development. The model suggests different approach in building software. Each model will suggest different sources and too ls to build a program. Every model or any software created that was built using an SDLC model has to plan before anything else. Project planning, feasibility study is very important aspect of building a software. It will answer the question of why would a developer build a software. Without planning, the software may not be able to perform or function as planned and feasibility study makes sure the program created is needed and will be appealing to the intended users. Project planning and feasibility studies is a stage where developers, project managers and research department will be working together. Developers will be the group who will be creating the software, project managers are the ones who makes sure the program will be done in time and the research department w ill show why an idea of a software will work.
In project development and feasibility studies stage of the SDLC, software engineers and developers should be able to:
Identify the Business Value:- Developing a software is not just creating a good software and
presenting them to the market with hopes that someone will actually use or buy it. Before the software is even created, the idea will be evaluated again and again. This objective has to be fulfilled by the company¶s researchers. They will be presenting the current market situation, current users need or World Wide Web that software engineers can fill. Estimate Investment and Reward on the Project:- In project planning, the investment on a
certain project has to be revealed. This will be the backbone of every project.
For
one,
investment will dictate how much the company will spend to create certain software. This is even
truer for companies that usually hire project based developers. Investment will dictate how many people will be working for the project. Aside from investment, project planning and feasibility studies should show how much the company will earn once the project is created. If it¶s just a tool for businesses, it should show how it can increase the productivity of the employees and its actual impact in financial sense. Analyze Feasibility:- Researchers or proponents of the software will actually show why the
software is needed in the actual business sense. Statistical data will always play a crucial role in proving why the particular software is good for public use. Most of the time, researchers will be interviewing individuals in order to get their opinion if they will use if that software is available in the market. It will also take a look at the possible competition and how will the software be different compared to other companies. Outline Technical Needs:- In project planning, developers should be able to come up with the
possible technical needs of the software. These are very important since without them, software development is nearly impossible. Within the realms of the budget, developers should get the best devices to help them in project development.
Procedures:
Within this stage, these are the procedures usually followed by software development companies. At the end of this stage, developers should be able to set the stage for the next phase of project development. Definition of business problem and scope Detailed Project Schedule is Outlined Project Approval Economic, Organizational, Technical, Resource, and Schedule Resource Management
Project Launching
Definition of business problem and scope
What are the functions of the projected software? Who will use it? How will the company earn from it? The reason why the software should be created is properly defined. Developers have to understand these needs in order to create a favorable plan as a response to these problems. Detailed Project Schedule is Outlined
Once the business problem has been outlined and proper responses have been laid through the projected functions of software, project managers should be able to outline the timeframe when the software will be available for public or intended users. Project Approval
By this time, the projected software is not yet presented to the upper management. Small software developers may have to bypass this point since they will be the same persons who will be approving the software. On the other hand, developers under larger companies will have to present their ideas to the upper management. This is where you¶ll realize the importance of management support for SDLC. Their final decision on the project will determine if the software building will push through or not. Economic, Organizational, Technical, Resource, and Schedule
In this stage, everything will be placed on paper: the needed financial resources, the needed back-up software and platforms, hardware devices and even the project number of personnel who will responsible to build the software.
Resource Management
After the paper, everything written on it should be implemented. First and foremost, additional hiring of developers should be in place. Hardware and software components should be installed and tested. Support staff should already be in place once production has started.
Project Launching
When everything is in place, it¶s time to get the ball rolling. Depending on the company size, project launching should be welcomed. There are companies who issue an official press release online and possibly in different media outlets. This will inform their potential clients and even competitors of the technological advantage o f the company to create this type of software.
5.
Software Requirement Analysis
.1 Introduction:5
Hotel Information System is an ideal software solution for Hospitality Industry that can be used at hotels, motels, inns, resorts, lodges, hostel, military guest houses, ranch, suites, apartments, medical centers and bed, breakfast operations. Our product Hotelier Hotel Information System is a comprehensive software suite consisting of integrated modules for various aspects of hotel management. The software is often referred to as Property Information System in the Hotel industry. Hotelier include in the software many requirement which is very essential for this project likes proper hotel information, booking system, creating new account. In our lodging software all modules are tightly integrated and all hotel programs are included in one price, meaning all modules are included at no additional cost regardless of your hotel size. Our Hotel Information software is developed for Microsoft Windows operating system using latest software developing techniques. Existing system of the hotel information system does not contain all the information of the hotels. In the present hotel information system doesn¶t provide the proper information and this system only provide the information about the hotels what it doesn¶t
provide the booking
module or the create new account of the customer. Then the present system can¶t contain the full information of the system. Need of the HIS:- A ready-to-use software that doesn't need a complex configuration to work
properly by internet avoiding huge investments on servers and databases into the properties. An always updated application to use the latest functionality available without any additional fees. An Hotel Information System provide the full information about the hotels for all the customers. Free account creation of the customer. Free Technical Support to ensure a proper hotel operation. Reservation of the customer will easy by using this software which contain the booking
of the single customer or may be in group. Reservations:- All reservations are easily handled with In consist On Demand
Front
Office,
showing all hotel's availability on the screen in order to allow an easy way to do individual and group reservations, knowing at every time the hotel's occupancy by room type in a given period of time. F unct ional ity Reservat ions Panel I nd ividual Reservat ion Group Reservat ion Ag encies and rates Deposits Reports:
Reservations Groups
Production and forecast Deposit
.2 5
General Description:-
The general description of the Hotel information system contain the description of the modules of the hotel information system. There are t hree modules of this project Search module Booking module Register or sign Up module
Search module contain the following points Where are you going? :- it means that the search of the hotels with the location of the
hotels. When? :- it means that the check-in and check-out date of the customer. How many people? :- it means that the no of the people want to stay in the hotel.
Booking
module contain the following description:-
Last name of the credit card holder. Pin number of the credit card.
Sign-Up module contain Contact information Email Confirm email Password Confirm password
Name Phone no Address Zip code Country Communication references Create your account
.2 Specific 5
Requirements
Hardware Specifications
Server:
Processor
Pentium-IV 2.8 GHz or above
RAM
512 MB or above
HDD
40 GB or above
Client:
Processor
RAM
HDD
Intel®Pentium®Dual
CPU
[email protected] or above 128 MB or above 20
B above
or
Software Specifications
MS Visual Studio 2010 Ultimate Programming Language
.NET, Application based Visual Studio Platform
Operating System
Microsoft Windows XP, Window Vista, Window 7
RDBMS
6. Design
SQL Server 2005
6 .1
System design
Home Page
Service Page
Click on the ³About Us´ link
Click on the ³Booking´ link
Click on ³Sign Up´ button
Click on ³Create User´ button
Click on ³Continue´ button then go on login page
After login open page of ³Reservation´.
6 .2
Design Notations:-
DFD
notation are which can be used in the project are following:
Firstly
we know about the DFD(Data
Flow
Diagram), it is a graphical representation of the
"flow" of data through an information system, modeling its process aspects. Often they are a preliminary step used to create an overview of the system which can later be elaborated. DFDs can also be used for the visualization of data processing (structured design). A DFD shows what kinds of data will be input to and output from the system, where the data will come from and go to, and where the data will be stored. It does not show information about the timing of processes, or information about whether processes will operate in sequence or in parallel.
Function
Database/File
Input/output
Flow
ER Diagram Notations:- ER diagram is called entity relationship diagram which mainly shows
the relationship b/w the real world entity. an entity-relationship model (ERM) is an abstract and
conceptual representation of data. Entity-relationship modeling is a database modeling method, used to produce a type of conceptual schema or semantic data model of a system, often a relational database, and its requirements in a top-down fashion. Diagrams created by this process are called entity-relationship diagrams, ER diagrams. The notations are used in ER diagram are following Symbol
ID
Property
Primary Attribute
Attributes
Process
Action
Flow Chart:- Flowcharts are the ideal diagrams for visually representing business processes. For
example, if you need to show the flow of a custom-order process through various departments
within your organization, you can use a flowchart. This paper provides a visual representation of basic flowchart symbols and their proposed use in communicating the structure of a welldeveloped web site, as well as their correlation in developing on-line instructional projects. A typical flowchart from older Computer Science textbooks may have the following kinds of symbols: Start and end symbols, represented as lozenges, ovals or rounded rectangles, usually containing
the word "Start" or "End", or another phrase signaling the start or end of a process, such as "submit enquiry" or "receive product". Arrows, showing what's called "flow of control" in computer science. An arrow coming from
one symbol and ending at another symbol signifies flow passes to the symbol the arrow po ints to. Processing steps, represented as rectangles. Examples: "Add 1 to X"; "replace identified part";
"save changes" or similar. Input/Output , represented as a para llelogram. Examples: Get X from the user; display X. Conditional (or decision ), represented as a diamond (rhombus). These typically contain a
Yes/No question or True/False test. This symbol is unique in that it has two arrows coming out of it, usually from the bottom point and right point, one corresponding to Yes or True, and one corresponding to No or False. The arrows should always be labeled. More than two arrows can be used, but this is normally a clear indicator that a complex decision is being taken, in which case it may need to be broken-down further, or replaced with the "pre-de fined process" symbol. A number of other symbols that have less universal currency, such as:
A Document represented as a rectangle with a wavy base ; A Manual input represented by a rectangle, with the top irregularly sloping up from left to right. An example would be to signify data-entry from a form; A Manual operation represented by a trapezoid with the longest parallel side upmost, to represent an operation or adjustment to process that can only be made manually. A Data File represented by a cylinder
A flowchart is described as "cross-functional" when the page is divided into different "lanes" describing the control of different organizational chart units. A symbol appearing in a particular "lane" is within the control of that organizational unit. This technique allows the analyst to locate the responsibility for performing an action or making a decision correctly, allowing the relationship between different organizational units with responsibility over a single process.
Decision
Process
Start
Stop
Predefined process
Off page connector
Flow
6.3 Detailed Design:USE CASE DIAGRAMS
Actors: Senior Management : Use the system for managerial decisions. Employee: Make reservations/cancellations Billing system: Maintain billing information. Scheduling system: Resolve conflicts and schedule the facilities in a manner that leads
to profit maximization. Facility Catalog: List of all rooms and various kinds of facilities available.
USE CASES: Validate User:
Used for the purpose of validating a user both employee and senior management. View Status of Reservations
Used by the senior management for obtaining the consolidated view of reservation, e.g. how many rooms were booked in a given month? What is the collection in a given month, what are the lean periods? Who are the customers who have made maximum reservations etc. Maintain Available room information
Keeps list of available rooms (these are plain rooms that can be used for any other purpose like conference wild parties etc). Maintain Available Wild Party Room information
Keeps list of wild party rooms that are already booked.
Maintain Classroom information
Maintains the list of classrooms that are currently booked.
Maintain Conference Room information
Maintains the list of conference rooms that are currently occupied. Maintain Banquet Request information
Maintains the list of banquet rooms that are already booked. Maintain dining room information
Scheduler maintains the booked dining rooms in the hotel. Maintain Rest Room information
Scheduler maintains the list of rest rooms that may be used by a facility for a given duration. This is used to reduce the co nflicts that could occur if the facilities are close by. Commit Facility reservation
This denotes the case where the Scheduler commits a reservation on behalf of the employee. This is the case where the internal Data Structures of the Scheduler are maintained. Also, as a result of the operation, the billing information is sent to t he billing system. Make facility reservation:
Denotes the situation where the employee on behalf of the customer makes a reservation for a facility in the hotel Cancel facility reservation:
Denotes the use case where t he employee cancels an existing reservation. Update facility:
Used by the senior management for the purpose o f adding/deleting an existing facility. For e.g. A new type of room may later be added by the senior management a marriage reception hall.
6 .4
ER Diagrams:-
Name User detail
Phone_No
Email
User_ID Booking
Customer
Hotel
Search-in
information
Hotel
Name
Location
Type
Brand
Addre
Address
Personal Information
Hotel¶s Booking
Customer
detail
Name Check_in Check Out
&
User_ID
User_ID
Name
Star rating
Brand
Register Customer
Hotel
Si n in
Sign Up
T
e
Personal Information
Booking
Personal Detail
Payment
Email
and
Password
6 .5 All
keys and Constraints:-
Key is set of one or more columns whose combined values are unique among all occurrences in
a given table. A Key is the relational means of specifying uniqueness. In other words, we can say that the concept of keys helps us to distinguish between the entities and relationships. There are five type of key. Which are following Primary key Candidate key Alternate key Composite key Foreign key
A primary key is an attribute of a relation which uniquely identifies each and every entity. A candidate key is set of attributes that can be used to uniquely identify an entity. A candidate keys can be a primary key but not all the candidate keys are primary key. Candidate keys other than primary key are known as alternate key. Composite key is a set of one or more attributes that when taken collectively allows us to identify
uniquely an entity. A foreign key is set of attribute of a table which refers to the primary key of some another table. A foreign key allows only those values which appear in the primary key of the table to which it refers or may be null.
Constraints provide the restriction if user wants to impose certain restriction on the data being
stored in a table. It control the data being entered in a table. There are five type of constraints which are following Primary key constraints Unique constraints Not null constraints
Foreign key constraints Check constraints
Primary key is applied to a column so that column can be used to uniquely identify each row in
the table. A table can have only one primary key. It also provide that primary key does not allow duplicate values and also not allow null values. Unique constraints is used for the candidate key columns so that they contain the unique values
for different entities. It also not allow duplicate values and unique key can accept null values. A table can have many unique constraints. Not null column constraints ensures that a table column cannot be left empty. When a not null
constraints is attached to a column beco mes a mandatory column. Foreign key is a column whose values are derived from the primary key of other table. Foreign
key enables us to establish the relationship between the tables. Check constraints is used to specify the data validation for a column. Check constraints is a
Boolean expression that is evaluated to either true or false.
