Maharashtra Board Class 11 Information Technology Theory Chapter 2 Introduction to DBMS PDF Download

Introduction To DBMS

2.1 Introduction

In our day to day life every person uses database in various ways. Like people use phone diary or phone book which contains name, address email id, phone number etc.

Doctor maintains medical history of patients. Librarian maintains records of their book details, issue date, return date. etc. Teacher keeps records of students like name, roll number, Marks etc. In these examples every one maintains records in a systematic manner.

In a computer system, we always maintain our records. At this point a database is very useful.

2.2 Definition Of A Database

Database is collection of interrelated data which helps in efficient retrieval, inserting and deleting of data. In exams, marks obtained by the student in subjects is data before it is entered in the report card. In a report card, the combined (marks) data of all subjects speaks about students performance. Thus when data is maintained in an organized manner it becomes meaningful or organized information.

Data Vs Information

Teacher's Note

Your teacher keeps marks in a register. One student's score is data. But when the teacher calculates the class average, that is information. Like in India, your Aadhaar number is data, but your identity proof made from Aadhaar is information.

Exam Trick

Remember: Data = raw facts. Information = useful facts. In exams, if they ask "Is 75 marks data or information?", answer "data". If they ask "Is class average data or information?", answer "information".

Points to Remember

Data is raw facts and numbers.
Information is data that is processed and useful.
Data alone does not help in making decisions.
Information helps us understand and make good choices.
Every business needs both data and information to work well.

2.3 Introduction To Database Management System (DBMS)

A database, often abbreviated as DB, is a collection of information organized in such a way that a computer program can quickly select desired pieces of data. A Database Management System (DBMS) is a software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data. It stores data in such a way that it becomes easier to retrieve, manipulate, and update information. Examples of popular DBMS are: MySQL, PostgreSQL, Access, Oracle, SQL Server, IBM, DB2 and Sybase.

2.4 Some Applications Of DBMS

Railway Reservation System: Database is required to keep record of ticket booking, train's departure and arrival status, status of seats available etc.

Library Management System: There are thousands of books in the library so it is very difficult to keep a record of all the books in a copy or register. So DBMS is used to maintain all the information related to book issue dates, name of the book, author and availability of the book.

Banking: People make thousands of transactions through banks daily and they can do this without going to the bank. So now banking has become so easy that by sitting at home bank customers can send or get money through banks. All this is possible just because of DBMS that manages all the bank transactions.

Universities and Colleges: Examinations are done online today and universities and colleges maintain all these records through DBMS. Student's registration details, results, courses and grades all the information is stored in a database.

Credit Card Transactions: For purchase of credit cards and all the other transactions are made possible only by DBMS. A credit card holder knows the importance of his information that all are secured through DBMS.

Social Media Sites: We all are on social media websites to share our views and connect with our friends. Daily, millions of users sign up for these social media accounts like Facebook, Twitter, Pinterest and Google plus. But how is all the information of users stored and how are we able to connect to other people? Yes, this is all because of DBMS.

Teacher's Note

When you book a train ticket online, DBMS checks if seats are available. When you check your bank balance from your phone, DBMS finds your account and shows you the money.

Exam Trick

Remember: DBMS is everywhere! Railways, banks, schools, Facebook, WhatsApp - all use DBMS. If the question asks "Where is DBMS used?", think of any place that stores information about many people.

Points to Remember

DBMS is used in railways, banks, schools, and social media.
Railway systems use DBMS to book tickets and track trains.
Banks use DBMS to store money and transaction details.
Schools use DBMS to store student marks and records.
Social media uses DBMS to store millions of user accounts.

2.5 Advantages Of DBMS

Reducing Data Redundancy: The file based data management systems contained multiple files that were stored in many different locations in a system or even across multiple systems. Because of this, there were sometimes multiple copies of the same file which lead to data redundancy. This is prevented in a database as there is a single database and any change in it is reflected immediately. Because of this, there is no chance of encountering duplicate data.

Sharing of Data: In a database, the users of the database can share the data among themselves. There are various levels of authorisation to access the data, and consequently the data can only be shared based on the correct authorisation protocols being followed. Many remote users can also access the database simultaneously and share the data between themselves.

Data Integrity: Data integrity means that the data is accurate and consistent in the database. Data Integrity is very important as there are multiple databases in a DBMS. All of these databases contain data that is visible to multiple users. So it is necessary to ensure that the data is correct and consistent in all the databases and for all the users.

Data Security: Data Security is vital concept in a database. Only authorised users should be allowed to access the database and their identity should be authenticated using a username and password. Unauthorised users should not be allowed to access the database under any circumstances as it violates the integrity constraints.

Privacy: The privacy rule in a database means only the authorized users can access a database according to its privacy constraints. There are levels of database access and a user can only view the data he is allowed to. For example - In social networking sites, access constraints are different for different accounts a user may want to access.

Backup and Recovery: Database Management System automatically takes care of backup and recovery. The users don't need to backup data periodically because this is taken care of by the DBMS. Moreover, it also restores the database after a crash or system failure to its previous condition.

Development and Maintenance Time: DBMS reduces application development and maintenance time. It supports many important functions that are common to many applications, accessing data stored in the DBMS, which facilitates the quick development of application.

Teacher's Note

If your computer crashes, DBMS automatically saves your data. Like in Google Docs, your document is automatically saved so you never lose your work.

Exam Trick

Remember: DBMS keeps data safe like a locker. It shares data safely, fixes mistakes, and keeps backup. Think "Safe, Share, Secure" for DBMS advantages.

Points to Remember

DBMS stops duplicate data from being stored twice.
DBMS lets many people use the same data safely.
DBMS keeps data correct and accurate always.
DBMS protects data with passwords and permissions.
DBMS automatically saves backup copies of all data.

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