Introduction to DBMS

UNIT-1

DBMS stands for Database Management System.

Data is nothing but raw facts and figures and unprocessed. Data becomes information when it is processed.

Database is a collection of inter-related and meaningful data which helps in efficient retrieval, insertion and deletion of data.

DBMS is software that allows creation, definition and manipulation of database, allowing users to store, process and analyze data easily. DBMS provides us with an interface or a tool, to perform various operations like creating database, storing data in it, updating data, creating tables in the database. Some examples of DBMS are Oracle, SQL Server, MySQL.
 

Applications where we use Database Management Systems are:

 Telecom: There is a database to keeps track of the information regarding calls made, network usage, customer details etc. Without the database systems it is hard to maintain that huge amount of data that keeps updating every millisecond.

Industry: Where it is a manufacturing unit, warehouse or distribution centre, each one needs a database to keep the records of ins and outs. For example distribution centre should keep a track of the product units that supplied into the centre as well as the products that got delivered out from the distribution centre on each day; this is where DBMS comes into picture.

Banking System: For storing customer info, tracking day to day credit and debit transactions, generating bank statements etc. All this work has been done with the help of Database management systems.

Sales: To store customer information, production information and invoice details.

Airlines: To travel though airlines, we make early reservations, this reservation information along with flight schedule is stored in database.

Education sector: Database systems are frequently used in schools and colleges to store and retrieve the data regarding student details, staff details, course details, exam details, payroll data, attendance details, fees details etc. There is a hell lot amount of inter-related data that needs to be stored and retrieved in an efficient manner.

Online shopping: You must be aware of the online shopping websites such as Amazon, Flipkart etc. These sites store the product information, your addresses and preferences, credit details and provide you the relevant list of products based on your query. All this involves a Database management system.

Characteristics of Database Management System

 
A database management system has following characteristics:

Data stored into Tables: Data is never directly stored into the database. Data is stored into tables, created inside the database. DBMS also allows having relationships between tables which makes the data more meaningful and connected. You can easily understand what type of data is stored where by looking at all the tables created in a database. 

Reduced Redundancy: In the modern world hard drives are very cheap, but earlier when hard drives were too expensive, unnecessary repetition of data in database was a big problem. But DBMS follows Normalisation which divides the data in such a way that repetition is minimised.

Data Consistency: On Live data, i.e. data that is being continuously updated and added, maintaining the consistency of data can become a challenge. But DBMS handles it all by
itself.

Support Multiple user and Concurrent Access: DBMS allows multiple users to work on it(update, insert, delete data) at the same time and still manages to maintain the data
consistency.

Query Language: DBMS provides users with a simple Query language, using which data can be easily fetched, inserted, deleted and updated in a database.

Security: The DBMS also takes care of the security of data, protecting the data from unauthorised access. In a typical DBMS, we can create user accounts with different access permissions, using which we can easily secure our data by restricting user access. DBMS supports transactions, which allows us to better handle and manage data integrity in real world applications where multi-threading, is extensively used

Advantage of DBMS over file system

 
There are several advantages of Database management system over file system. Few of them are as follows:

No redundant data: Redundancy removed by data normalization. No data duplication saves storage and improves access time.

Data Consistency and Integrity: As we discussed earlier the root cause of data inconsistency is data redundancy, since data normalization takes care of the data redundancy, data inconsistency also been taken care of as part of it

Data Security: It is easier to apply access constraints in database systems so that only authorized user is able to access the data. Each user has a different set of access thus data is secured from the issues such as identity theft, data leaks and misuse of data.

Privacy: Limited access means privacy of data.

Easy access to data – Database systems manages data in such a way so that the data is easily accessible with fast response times.

Easy recovery: Since a database system keeps the backup of data, it is easier to do a full recovery of data in case of a failure.

Flexible: Database systems are more flexible than file processing systems