A database is a
collection of interrelated data’s stored in a database server;
these data’s will be stored in the form of tables. The primary
aim of database is to provide a way to store and retrieve database information
in fast and efficient manner.
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There are number of characteristics that differs from traditional file
management system. In file system approach, each user defines and implements
the needed files for a specific application to run. For example in sales
department of an enterprise, One user will be maintaining the details
of how many sales personnel are there in the sales department and their
grades, these details will be stored and maintained in a separate file.
Another user will be maintaining the salesperson salary details working
in the concern, the detailed salary report will be stored and maintained
in a separate file. Although both of the users are interested in the
data’s of the salespersons they will be having their details in
a separate files and they need different programs to manipulate their
files. This will lead to wastage of space and redundancy or replication
of data’s, which may lead to confusion, sharing of data among various
users is not possible, data inconsistency may occur. These files will
not be having any inter-relationship among the data’s stored in
these files. Therefore in traditional file processing every user will
be defining their own constraints and implement the files needed for
the applications.
In database approach,
a single repository of data is maintained that is defined once and then
accessed by many users. The fundamental characteristic of database approach
is that the database system not only contains data’s but it contains
complete definition or description of the database structure and constraints.
These definitions are stored in a system catalog, which contains the
information about the structure and definitions of the database. The
information stored in the catalog is called the metadata, it describes
the primary database. Hence this approach will work on any type of database
for example, insurance database, Airlines, banking database, Finance
details, and Enterprise information database. But in traditional file
processing system the application is developed for a specific purpose
and they will access specific database only.
The other main characteristic
of the database is that it will allow multiple users to access the database
at the same time and sharing of data is possible. The database must
include concurrency control software to ensure that several users trying
to update the same data at the same time, it should maintain in a controlled
manner. In file system approach many programmers will be creating files
over a long period and various files have different format, in various
application languages.
Therefore there is possibility of information getting duplicated, this
redundancy is storing same data multiple times leads to higher costs
and wastage of space. This may result in data inconsistency in the application,
this is because update is done to some of the files only and not all
the files. Moreover in database approach multiple views can be created.
View is a tailored representation of information contained in one or
more tables. View is also called as “Virtual table” because
view does not contain physically stored records and will not occupy
any space.
A multi-user database whose users have variety of applications must
provide facilities for defining multiple views. In traditional file
system, if any changes are made to the structure of the files if will
affect all the programs, so changes to the structure of a file may require
changing of all programs that access the file. But in case of database
approach the structure of the database is stored separately in the system
catalog from the access of the application programs. This property is
known as program-data independence.
Database can be
used to provide persistent storage for program objects and data structures
that resulted in object oriented database approach. Traditional systems
suffered from impedance mismatch problem and difficulty in accessing
the data, which is avoided in object oriented database system. Database
can be used to represent complex relationships among data’s as
well as to retrieve and update related data easily and efficiently.
It is possible to define and enforce integrity constraints for the data’s
stored in the database. The database also provides facilities for recovering
hardware and software failures. The backup and recovery subsystem is
responsible for recovery. It reduces the application development time
considerably when compared to the file system approach and availability
of up-to-date information of all the users. It also provides security
to the data’s stored in the database system.
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