Components and Advantages of DBMS

COMPONENTS AND ADVANTAGES OF DBMS
BY: SHUBHAM JOON
ASSIGNMENT 1

WHAT IS DBMS??!!
• A database-management system (DBMS) is a computer-software application that interacts
with end-users, other applications, and the database itself to capture and analyse data. A
general-purpose DBMS allows the definition, creation, querying, update, and administration of
databases. Well-known DBMSs include MySQL, PostgreSQL, MongoDB, MariaDB, Microsoft SQL
Server, Oracle, Sybase, SAP HANA, MemSQL, SQLite and IBM DB2.

COMPONENTS OF DBMS
A database management system (DBMS) consists of several components. Each component plays very
important role in the database management system environment. The major components of database
management system are:
• Software
• Hardware
• Data
• Procedures
• Users (or people)

1. SOFTWARE
• The main component of a DBMS is the software. It is the set of programs used to handle the database
and to control and manage the overall computerized database
• DBMS software itself, is the most important software component in the overall system
• Operating system including network software being used in network, to share the data of database
among multiple users.
• Application programs developed in programming languages such as C++, Visual Basic that are used to to
access database in database management system. Each program contains statements that request the
DBMS to perform operation on database. The operations may include retrieving, updating, deleting
data etc . The application program may be conventional or online workstations or terminals.

2. HARDWARE
Hardware consists of a set of physical electronic devices such as computers (together with associated I/O
devices like disk drives), storage devices, I/O channels, electromechanical devices that make interface
between computers and the real world systems etc, and so on. It is impossible to implement the DBMS
without the hardware devices, In a network, a powerful computer with high data processing speed and a
storage device with large storage capacity is required as database server.

3.DATA
Data is the most important component of the DBMS.
The main purpose of DBMS is to process the data. In DBMS,
databases are defined, constructed and then data is stored,
updated and retrieved to and from the databases. The database
contains both the actual (or operational) data and the metadata
(data about data or description about data).

4. PROCEDURES
• Procedures refer to the instructions and rules that help to design the database and to use the DBMS.
The users that operate and manage the DBMS require documented procedures on hot use or run the
database management system. These may include.
• Procedure to install the new DBMS.
• To log on to the DBMS.
• To use the DBMS or application program.
• To make backup copies of database.
• To change the structure of database.
• To generate the reports of data retrieved
• from database.

5. USERS (OR PEOPLE)
The users are the people who manage the databases and perform different operations on the databases in
the database system. There are three kinds of people who play different roles in database systems:-
1. Application Programmer
2. Database Administrators
3. End-Users

1. Naïve Users: These are the users who are constantly querying and updating the database. E.g. Bank
clerk, Railway clerk.
2. Casual Users: These are the people who use the database occasionally. E.g. ATM users.
3. Sophisticated Users: People who use for their complex requirements. E.g. Business and Financial
analyst.
4. Standalone Users: These are the users who maintain and use the database for their personal queries.
End Users:
Application Programmers
The people who write application programs in programming languages (such as Visual Basic, Java, or C++) to
interact with databases are called Application Programmer.
Database Administrators
A person who is responsible for managing the overall database management system is called database
administrator or simply DBA.
End-Users
The end-users are the people who interact with database management system to perform different
operations on database such as retrieving, updating, inserting, deleting data etc.

1. CONTROLLING DATA REDUNDANCY
In non-database systems (traditional computer file
processing), each application program has its own
files. In this case, the duplicated copies of the same
data are created at many places. In DBMS, all the
data of an organization is integrated into a single
database. The data is recorded at only one place in
the database and it is not duplicated.
For example, the General Office file and the account file contains several items that are identical. When they are
converted into database, the data is integrated into a single database so that multiple copies of the same data are
reduced to-single copy.
In DBMS, the data redundancy can be controlled or reduced but is not removed completely. Sometimes, it is
necessary to create duplicate copies of the same data items in order to relate tables with each other.
By controlling the data redundancy, you can save storage space. Similarly, it is useful for retrieving data from
database using queries.

2. DATA CONSISTENCY
By controlling the data redundancy, the data
consistency is obtained. If a data item appears
only once, any update to its value has to be
performed only once and the updated value
(new value of item) is immediately available to
all users.
If the DBMS has reduced redundancy to a
minimum level, the database system enforces
consistency. It means that when a data item
appears more than once in the database and is
updated, the DBMS automatically updates each
occurrence of a data item in the database.

3. DATA SHARING
In DBMS, data can be shared by authorized users
of the organization. The DBA manages the data
and gives rights to users to access the data. Many
users can be authorized to access the same set of
information simultaneously. The remote users can
also share same data. Similarly, the data of same
database can be shared between different
application programs.

4. DATA INTEGERATION
In DBMS, data in database is stored in tables.
A single database contains multiple tables
and relationships can be created between
tables (or associated data entities). This
makes easy to retrieve and update data.
5. INTEGRITY CONSTRAINTS
Integrity constraints or consistency rules can
be applied to database so that the correct
data can be entered into database. The
constraints may be applied to data item
within a single record or they may be applied
to relationships between records.

6. DATA SECURITY
It is the protection of the database from unauthorized users.
Only the authorized persons are allowed to access the database.
Some of the users may be allowed to access only a part of database
i.e., the data that is related to them or related to their department.
Mostly, the DBA or head of a department can access all the data in
the database. Some users may be permitted only to retrieve data,
whereas others are allowed to retrieve as well as to update data. The
database access is controlled by the DBA. He creates the accounts of
users and gives rights to access the database. Typically, users or group
of users are given usernames protected by passwords.
For example,
If you have an account of e-mail in the "hotmail.com" (a popular website),
then you have to give your correct username and password to access your
account of e-mail. Similarly, when you insert your ATM card into the Auto
Teller Machine (ATM) in a bank, the machine reads your ID number printed
on the card and then asks you to enter your pin code (or password).
In this way, you can access your account.

7. DATA ATOMICITY
A transaction in commercial databases is
referred to as atomic unit of work. For
example, when you purchase something
from a point of sale (POS) terminal, a
number of tasks are performed such as;
a) Company stock is updated.
b) Amount is added in company's account.
c) Sales person's commission increases etc.
All these tasks collectively are called an atomic
unit of work or transaction. These tasks must be
completed in all; otherwise partially completed
tasks are rolled back. Thus through DBMS, it is
ensured that only consistent data exists within
the database.

8. DATABASE ACCESS LANGUAGE
Most of the DBMSs provide SQL as standard database access
language. It is used to access data from multiple tables of a
database.
9. DEVELOPMENT OF APPLICATION
The cost and time for developing new applications is also
reduced. The DBMS provides tools that can be used to develop
application programs. For example, some wizards are available
to generate Forms and Reports. Stored procedures
(stored on server side) also reduce the size of application
programs.
10. CREATING FORMS
Form is very important object of DBMS. You can create Forms
very easily and quickly in DBMS, once a Form is created, it can
be used many times and it can be modified very easily. The
created Forms are also saved along with database and behave
like a software component. A Form provides very easy way
(user-friendly interface) to enter data into database, edit data, and display data from
database. The non-technical users can also perform various operations on databases
through Forms without going into the technical details of a database.

11. REPORT WRITERS
Most of the DBMSs provide the report writer tools used to create
reports. The users can create reports very easily and quickly.
Once a report is created, it can be used many times and it can be
modified very easily. The created reports are also saved along
with database and behave like a software component.
12. CONTROL OVER CONCURRENCY
In a computer file-based system, if two users are allowed to access
data simultaneously, it is possible that they will interfere with each
other. For example, if both users attempt to perform update
operation on the same record, then one may overwrite the values
recorded by the other. Most DBMSs have sub-systems to control the
concurrency so that transactions are always recorded" with
accuracy.

13. BACKUP AND RECOVERY PROCEDURES
In a computer file-based system, the user creates the backup of data regularly to
protect the valuable data from damaging due to failures to the computer system or
application program. It is a time consuming method, if volume of data is large. Most
of the DBMSs provide the 'backup and recovery' sub-systems that automatically
create the backup of data and restore data if required. For example, if the computer
system fails in the middle (or end) of an update operation of the program, the
recovery sub-system is responsible for making sure that the database is restored to
the state it was in before the program started executing.

14. DATA INDEPENDENCE
The separation of data structure of database from
the application program that is used to access data
from database is called data independence. In DBMS,
database and application programs are separated
from each other. The DBMS sits in between them.
You can easily change the structure of database
without modifying the application program. For
example you can modify the size or data type of a
data items (fields of a database table).
On the other hand, in computer file-based system,
the structure of data items are built into the
individual application programs. Thus the data is
dependent on the data file and vice versa.
ADVANCED CAPABILITIES OF DBMS
DBMS also provides advance capabilities for online access
and reporting of data through Internet. Today, most of the
database systems are online. The database technology is
used in conjunction with Internet technology to access data
on the web servers.

Components and Advantages of DBMS

Components and Advantages of DBMS

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