Unit I
Introduction to Database Management System
DATA: Data is a collection of raw facts and figures that have no meaning by themselves.
Characteristics of Data
Raw facts
Unprocessed
Has little meaning by itself
Used as input
Suppose your teacher writes:
Ravi
85
Class 10
Roll No. 25
These are just separate facts. This is called Data.
Real-Life Examples :Your name,Your roll number, Your age,Your marks,Your phone number All these are examples of Data.
INFORMATION:Information is processed and meaningful data.
After processing data, we get useful results called Information.
Example:
METADATA 
Metadata means "Data about Data."
It tells us how the data is stored.
Easy Example
Suppose your Aadhaar card contains:
Name
Date of Birth
Address
Aadhaar Number
DATABASE:
A Database is an organized collection of related data stored in one place.
Example:
Gram Panchayat keeps records of
Birth Certificates
Death Certificates
House Tax
Water Tax
Pension Details
Earlier these were stored in books.
Now they are stored in computers.
That computer storage is called a Database
Characteristics of Database
Organized
Easy to search
Easy to update
Secure
Stores large amounts of data
Reduces duplicate records
Database will be used in following scenarios
Purchases from the supermarket
Purchases using your credit card
Booking a vacation with a travel agent
Using the local library
Taking out insurance
Renting a DVD
Using the Internet
Studying at College
DATABASE MANAGEMENT SYSTEM
A Database Management System (DBMS) is software used to create, store, update, search, and manage databases.
Examples of DBMS : MySQL, Oracle Database, Microsoft SQL Server, PostgreSQL,
SQLite
Bank Example When you visit a bank, The employee enters your account number.
Within seconds,
Name
Balance
Transactions
appear on the screen. This happens because the bank uses a DBMS.
College Example Suppose your college has 10,000 students.
The principal wants to know Ravi's attendance.
Without DBMS
Search thousands of papers
With DBMS
Type Roll Number
Record appears in seconds
FILE BASED SYSTEM
1.Discuss about Filebased System and it’s drawbacks?
Ans:
Before the invention of Database Management Systems (DBMS), organizations stored information using a Traditional File-Based System.
A File-Based System is a traditional method of storing data in separate files. Each department or application keeps its own files, and there is no central database
Characteristics of File-Based System
Data is stored in separate files.
Each department has its own files.
No centralized storage.
Files are independent.
Difficult to share data between departments.
Example:
Imagine a college has three departments:
Admissions Department
Library
Examination Branch
Each department maintains its own student records.
Notice that the student's name and roll number are repeated in every file.
This is a File-Based System.
DRAWBACKS OF FILE-BASED SYSTEM :
1.Separation and isolation of data
When data is in separate files, it is more difficult to access data . This difficulty is arises if we require data from more than two files
2.Duplication of data
The same data is stored many times in different files. Duplication is wasteful. It costs time and money to enter the data more than once. It takes up additional storage space, again with associated costs.
3.Data dependence
Programs are directly connected to the file structure. If the file structure changes, the program must also be changed.
Example
Suppose we add a new field:
Phone Number
All programs using the student file must be modified.
This requires extra time and effort.
4.Incompatible File Formats
Different software stores data in different formats.Because of this, files cannot be easily combined.
Example
One department uses C Language software. Another department uses COBOL software.Their files may not work together.
5.Fixed Queries
Users can only view reports that the programmer has already created.They cannot ask new questions without modifying the program.
Example
The Principal asks:
"Show students who scored above 80 and borrowed DBMS books."
If this report was not programmed earlier, the system cannot generate it.
A programmer must write a new program.
6. Too Many Programs Since every department develops its own software,
the organization ends up with:
Many files
Many programs
This makes the system difficult to manage.
7. Poor Backup and Recovery
If the computer crashes or files are deleted, recovering the data is difficult.
Sometimes, the data may be lost permanently.
8. No Data Sharing
Only one user can access a file at a time. Different departments cannot easily share information.
Example The Library needs student addresses.
It must ask the Admission Department instead of directly accessing the data.
A Database Management System (DBMS) was introduced to solve the problems of the Traditional File-Based System
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