This document provides an overview of database management systems (DBMS). It defines data and databases, and explains that a DBMS organizes data into tables and indexes to make it easily accessible. A DBMS offers advantages over file systems like reducing data redundancy, improving data sharing and concurrency, and enforcing data integrity. The document also describes the typical structure of a DBMS and roles of users like administrators, designers, and end users.

1. DBMS
Presented by
Prof. Dipali Y. Jadhav
Mamasaheb Mohol college,kothrud,pune.

2. • What is Data?
• Data is a collection of a distinct small unit of information. It
can be used in a variety of forms like text, numbers, media,
bytes, etc. it can be stored in pieces of paper or electronic
memory, etc.
• Word 'Data' is originated from the word 'datum' that means
'single piece of information.' It is plural of the word datum.
• In computing, Data is information that can be translated into a
form for efficient movement and processing. Data is
interchangeable.

3. • What is Database?
• A database is an organized collection of data, so that it can be easily
accessed and managed.
• You can organize data into tables, rows, columns, and index it to
make it easier to find relevant information.
• For example: The college Database organizes the data about the
admin, staff, students and faculty etc.
• Using the database, you can easily retrieve, insert, and delete the
information.
• The main purpose of the database is to operate a large amount of
information by storing, retrieving, and managing data.
• There are many dynamic websites on the World Wide Web
nowadays which are handled through databases. For example, a
model that checks the availability of rooms in a hotel. It is an
example of a dynamic website that uses a database.
• There are many databases available like MySQL, Sybase, Oracle,
MongoDB, Informix, PostgreSQL, SQL Server, etc.
• Modern databases are managed by the database management
system (DBMS).

4. Advantagesof DBMSover File system–
• Data redundancy and inconsistency – Redundancy is the concept
of repetition of data i.e. each data may have more than a single
copy.
• The file system cannot control redundancy of data as each user
defines and maintains the needed files for a specific application to
run. There may be a possibility that two users are maintaining same
files data for different applications.
• Hence changes made by one user does not reflect in files used by
second users, which leads to inconsistency of data.
• Whereas DBMS controls redundancy by maintaining a single
repository of data that is defined once and is accessed by many
users. As there is no or less redundancy, data remains consistent.

5. • Data sharing – File system does not allow sharing of data or sharing is
too complex. Whereas in DBMS, data can be shared easily due to
centralized system.
• Data concurrency – Concurrent access to data means more than one
user is accessing the same data at the same time. Problem occur when
changes made by one user gets lost because of changes made by other
user.
• File system does not provide any procedure to stop anomalies. Whereas
DBMS provides a locking system to stop anomalies to occur.
• Data searching – For every search operation performed on file system, a
different application program has to be written. While DBMS provides
inbuilt searching operations. User only have to write a small query to
retrieve data from database.
• Data integrity – There may be cases when some constraints need to be
applied on the data before inserting it in database. The file system does
not provide any procedure to check these constraints automatically.
Whereas DBMS maintains data integrity by enforcing user defined
constraints on data by itself.

6. Structure of DBMS

7. DBMS USERS
• A typical DBMS has users with different rights and permissions
who use it for different purposes. Some users retrieve data
and some back it up. The users of a DBMS can be broadly
categorized as follows −
• Administrators − Administrators maintain the DBMS and are
responsible for administrating the database. They are
responsible to look after its usage and by whom it should be
used. They create access profiles for users and apply
limitations to maintain isolation and force security.
Administrators also look after DBMS resources like system
license, required tools, and other software and hardware
related maintenance.

8. • Designers − Designers are the group of people who actually
work on the designing part of the database. They keep a close
watch on what data should be kept and in what format. They
identify and design the whole set of entities, relations,
constraints, and views.
• End Users − End users are those who actually reap the
benefits of having a DBMS. End users can range from simple
viewers who pay attention to the logs or market rates to
sophisticated users such as business analysts.