Database

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DATABASE
DEFINITIONS:
“A database is a collection of information that is organized so
that it can easily be accessed, managed, and updated.”
Or
A DATABASE is an organized collection of data.[1] It is the
collection of schemas, tables, queries, reports, views, and other
objects.
DATABASE:
Database is an organized collection of related data. The
word organized means that data is stored in such a way that the user
can store, manipulate and retrieve data easily. The word related means
that database is normally created to store data about a particular topic.
For example, if you create a database for students, it will contain the
data about the students such as roll no, name, address and other
information about the students. Similarly, if the database is about the
employees of an organization, it will contain the data of the employees
such as employee ID, grade and salary etc. All data in the database is
arranged in tables.
 TABLE:
Table is the fundamental object of database structure. The
basic purpose of a table is to store data. It consists of rows and column.

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A table is a very convenient way to store data. The user can easily
manipulate the data in a table.
Serial No Name Roll no Total marks Marks obtained
1 Usman 554480 1100 850
2 Abdullah 554481 1100 796
3 Ejaz 554482 1100 725
 ROW/ RECORD:
Rows are the horizontal part of the table. It is a
collection of related fields. For example, there are three rows in the
above table. Each row contains a record of different person.
1 Usman 554480 1100 850
 COLUMN/ FIELD:
Columns are the vertical part of the table. For
example, all values under Name field in the above table make a column.
Name
Usman
Abdullah
Ejaz
EXAMPLES OF DATABASE:
 PHONE DIRECTORY
Phone directory is a simple example of a
database. A phone directory stores the phone numbers of different

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persons. You can search any phone number from the phone directory
easily because all phone numbers are stored in an organized way.
 LIBRARY
A library contains thousands of books. It is very
difficult to handle the records of all these books without a database. A
database system can be used to store the records of books, members of
the library, issuance and recovery of the books etc. The user can use the
database to search the required books easily. This database can help a
lot for doing research work.
 ACCOUNTS
A database is used to control the accounts
system of an organization. The accounts database keeps record of all
financial transactions. It can easily perform different calculations to find
the information about the business such as annual profit, trial balance
and ledger etc.
 COLLEGES
A college has many students in different classes.
A database may be used to keep the records of the students, fee
transactions, examination, information and other data about the
college. You can also store the attendance of the student in the
database.
DATABASE MANAGEMENT SYSTEM:
“A database management system (DBMS) is system software for
creating and managing databases. The DBMS provides users and
programmers with a systematic way to create, retrieve, update
and manage data.”

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WHAT IS DBMS?
 DBMS is the collection of software for organizing the information in a
database that might contain routines of data input, verification, storage,
retrieval, and combination.
 DBMS are applications that interact with user to others applications and
database it to capture and analyse data.
 DBMS is a suit of computer software providing interface between user's and
the database.
 They are so closely related the term database when used casually often
refers to both DBMS and the data its manipulates.
OBJECTIVES OF DBSM:
These are the important objectives of DBSM.
 SHAREABILITY:
An ability to share data resources is a
fundamental objective of database management. In its fullest
interpretation, this means different people and different processes
using the same actual data at virtually the same time.
 AVAILABILITY:
Availability means bringing the data of an
organization to the users of that data. They system which manages data
resources should be easily accessible to the people within n
organization – making the data available when and where it is needed,
and in the manner and form in which it is needed.

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 INTEGRITY:
Integrity means your data is authentic and consistent.
DBMS has various validity checks that make your data completely
accurate and consistence.
 EVOLVABILITY:
Evolvability refers to the ability of the DBMS to
change in response to growing user needs and advancing technology.
Evolvability is the system characteristic that enhances future availability
of the data resources. Evolvability covers expansion or contraction,
both of which may occur as the system changes to fit the ever changing
needs and desires of the using environment.
COMPONENTS OF DBSM:
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:
 Data
 Software
 Hardware
 Personnel
 Procedure
 DATA:
Data is the most important component of the
DBMS. The main purpose of DBMS is to process the data. In DBMS,

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databases are defined, constructed and then data is stored, updated
and retrieved to and from the databases.
 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.
o DBMS software itself is the most important software component in the
overall system.
o Operating system including network software being used in network, to
share the data of database among multiple users.
o Application programs developed in programming languages such as
C++, Visual Basic that are used 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.
 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.

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 PERSONNEL:
The people related to database system
are called personnel. The different types of persons in database system
are as follows:
o Application Programmers
o Database Administrators
o End-Users
o 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.
o DATABASE ADMINISTRATORS:
A person who is responsible for managing the overall database
management system is called database administrator or simply DBA.
o 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.
 PROCEDURE:
These are the instructions and rules that
assist on how to use the DBMS, and in designing and running the
database, using documented procedures, to guide the users that
operate and manage it.

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FEATURES OF DBSM:
There are a variety of DBMS database management
tools that provide different features and functionality. Here are the
most probable and must-have features of a typical DBMS:
 DATA STRUCTURING
All information in a digital repository is
organized into a clear hierarchical structure with records, tables or
objects. Every piece of information that you can add to your database
will be organized in a kind of catalogue, so it will be easier for you to
search and update your records later on.
 DATABASE CUSTOMIZATION
Along with default and necessary
elements (records, tables, or objects) that compose a database's
structure, there can be created custom elements that meet specific
needs of users.
 DATA RETRIEVAL
DBMS database management
system accepts data input from users and stores it. Users can access the
database later on to retrieve their records as a file, printed, or viewed
on the screen.
 QUERY LANGUAGES
A typical DBMS makes it possible to use
query languages for collecting, searching, sorting, modifying and other
activities that help users manipulate their records in the database.

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 MULTI-USER ACCESS
DBMS provides multiple users access to all
types of information stored in one and the same data store. There is
also a security feature that prevents some users from viewing and/or
modifying certain data types.
 METADATA
DBMS database management software provides a metadata
library (or a data dictionary) that describes how the database is
organized and what elements (objects, related files, records, etc.)
compose its structure.
TYPES OF DATABASE MODELS:
There are three types of logical database models. These models are as
follows:
 HIERARCHICAL MODEL
 NETWORK MODEL
 RELATIONAL MODEL
 HIERARCHICAL MODEL:
 Data is organized into a simple tree like structure.
 It was the first DBMS Model (1960's).
 Data is Stored Hierarchically either in top down or
bottom up.

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 Data is represented by using parent children
relationship.
 Each parent can have many children but children
have only one parent.
 All attributes of specific records are listed under
entity types.
 Entity type is nothing but a table.
 Each individual record is represented as a row.
 Each individual attributes is represented as a
columns.
 This model was primarily used by IBM’s Information
Management Systems in the 60s and 70s.
 But they
are rarely
seen today
due to certain operational
inefficiencies.
 NETWORK MODEL:
 Like hierarchical model this uses pointers towards data
 Allows each record to have multiple parent child
records.

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ENTITY 1 ENTITY 4
ENTITY 2 ENTITY 5
ENTITY 3 ENTITY 6
 Not necessarily a downwards tree structure.
 Its diagram is more complicated.
 Entities are organized in a graph in which some
entities can be
accessed through
several
paths.
 It is
more flexible than
hierarchical model.
 RELATIONAL MODEL:
 Relational model is the most commonly used database
model.
 It is more flexible than hierarchical and network
database models.
 The relational model consists of simple relations.
 A relation is a term used for table. A relation represents
a particular entity.
 It is used to store information about the entity. The
relationships are based on the data of the entities.
 The relationship between entities is represented by
following
diagram.

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ADVANTAGES OF DATABASE:
 ABILITY TO STORE LARGE AMOUNTS OF
INFORMATION
This ability is essential for large companies with a large number of
customers and this volume of information must be handled very
precisely.
 SHARING INFORMATION
Databases allow users to share common information. Therefore, if you
have a business with different company locations you can share your
data at same time with the different business locations.
 HAVING QUICK ACCESS TO INFORMATION
The information is obtained quickly and easily, which greatly facilitates
the work and allows you having better customer service.
 ELIMINATING DUPLICATIONS
By centralizing all information in a database you prevent duplication of
existing information which usually presents a common problem in
business.
 INCREASING PRODUCTIVITY
Access to information is faster now than ever before. Information will
be structured without any duplication – allowing you to work better,
faster with increased productivity in your company.

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 REDUCING STORAGE SPACE
Information is digitized so it takes less space than when stored on
paper. You will always have certain documents that will have to be on
paper. Try to scan all of your documentation. It is a large initial effort it
will make all your tasks easier.
 INFORMATION SECURITY
A database can have several parts depending on users. You can limit
certain access to certain parts of the data for certain users. That way
the security and confidentiality of data will be guaranteed and secured.
 EASY MAINTENANCE
As the information is digitized it is easier and economical to carry out
any maintenance.
DISADVANTAGES OF DATABASE:
Although there are many advantages of DBMS, the DBMS may also have
some minor disadvantages. These are:
 COST OF HARDWARE AND SOFTWARE
A processor with high speed of data processing and memory of large
size is required to run the DBMS software. It means that you have to
upgrade the hardware used for file-based system. Similarly, DBMS
software is also very costly,
 COST OF DATA CONVERSION
When a computer file-based system is replaced with database system,
the data stored into data file must be converted to database file. It is

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very difficult and costly method to convert data of data file into
database. You have to hire database system designers along with
application programmers. Alternatively, you have to take the services of
some software house. So a lot of money has to be paid for developing
software.
 COST OF STAFF TRAINING
Most database management system is often complex systems so the
training for users to use the DBMS is required. Training is required at all
levels, including programming, application development, and database
administration. The organization has to be paid a lot of amount for the
training of staff to run the DBMS.
 DATABASE DAMAGE
In most of the organization, all data is integrated into a single database. If
database is damaged due to electric failure or database is corrupted on
the storage media, your valuable data may be lost forever.
 It increases opportunity for person or groups outside the organization to
gain access to information about the firms operation.
 It increases opportunity for fully training person within the
organization to misuse the data resources intentionally.
CONCLUSION:
A well-designed database will ensure that your data is accurate,
that you can extract the information you need, and that your database can
evolve as your requirements change. It is a systematic operational system which
consists of tools making data, data saving and data manipulation an easier task.

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DBMS is the majorly used throughout the world for data handling. Thus it’s a
good data manager till today.

Database

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