SOCSAMS e-learning
DATABASE
MANAGEMENT SYSTEM
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SOCSAMS e-learning
DATABASE
MANAGEMENT SYSTEM
A database
system is
basically a
computer
based record
keeping
system
A DBMS is a
collection of
interrelated
data and a set
of programs to
access those
data
The primary
goal of a
DBMS is to
provide a way
to store and
retrieve
database
information
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SOCSAMS e-learning
Basic Terms
•
Data
•
Information
•
Database
•
Database System
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SOCSAMS e-learning
Basic Terms
•
Data
•
Information
•
Database
•
Database System
Anything can be a data.
(raw facts & figures)
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SOCSAMS e-learning
Basic Terms
•
Data
•
Information
•
Database
•
Database System
Processed data.
(meaningful data)
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SOCSAMS e-learning
Basic Terms
•
Data
•
Information
•
Database
•
Database System
An organised, persistent
collection of logically related
data.
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SOCSAMS e-learning
Basic Terms
•
Data
•
Information
•
Database
•
Database System
A computer based record
keeping system, whose
overall purpose is to record
and maintain information. It
manages the database of
an enterprise.
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What is the need of a Database
Management System ?
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SOCSAMS e-learning
The File Based System
File based systems are an early attempt to computerise the
manual filing system.This works well when the number of
items to be stored is small or the process is only needed to store
and retrieve information.
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Students
University
Courses
Application by COBOL program
Students
Faculty
Application by C program
Fee
Collection
Subject
Department
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SOCSAMS e-learning
Database System vs. File Based System
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Limitations of File Based System
•
Separation and Isolation of Data
•
Duplication of Data
•
Inconsistent Data
•
Data Dependence
•
Incompatible File Formats
•
Fixed Queries
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SOCSAMS e-learning
Limitations of File Based System
•
Separation and Isolation of Data
•
Duplication of Data
•
Inconsistent Data
•
Data Dependence
•
Incompatible File Formats
•
Fixed Queries
When the data is stored in
separate files it becomes
difficult to access.
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SOCSAMS e-learning
Limitations of File Based System
•
Separation and Isolation of Data
•
Duplication of Data
•
Inconsistent Data
•
Data Dependence
•
Incompatible File Formats
•
Fixed Queries
Decentralised approach
leads to uncontrolled
duplication of data, which
leads wastage of storage
space, time and money.
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SOCSAMS e-learning
Limitations of File Based System
•
Separation and Isolation of Data
•
Duplication of Data
•
Inconsistent Data
•
Data Dependence
•
Incompatible File Formats
•
Fixed Queries
Changes made by different
people for the same
information differently or
Entering a wrong data.
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SOCSAMS e-learning
Limitations of File Based System
•
Separation and Isolation of Data
•
Duplication of Data
•
Inconsistent Data
•
Data Dependence
•
Incompatible File Formats
•
Fixed Queries
The physical structure and
storage of data files and
records are defined in the
application code.
Program Data Dependence
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SOCSAMS e-learning
Limitations of File Based System
•
Separation and Isolation of Data
•
Duplication of Data
•
Inconsistent Data
•
Data Dependence
•
Incompatible File Formats
•
Fixed Queries
The structure of the file
embedded in application
program totally dependent
on the programming
language. This
incompatibility makes them
difficult to process jointly.
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SOCSAMS e-learning
Limitations of File Based System
•
Separation and Isolation of Data
•
Duplication of Data
•
Inconsistent Data
•
Data Dependence
•
Incompatible File Formats
•
Fixed Queries
Query or reports needed by
the organization has to be
developed by the application
programmer.
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Database System
A database system involves four major components
•
Data
•
Hardware
•
Software
•
Users
Provides the enterprise with centralized
control of its data.
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SOCSAMS e-learning
Database System
A database system involves four major components
•
Data
•
Hardware
•
Software
•
Users
Provides the enterprise with centralized
control of its data.
A database contains not only the data
but also the complete definition of the
database structure and constraints.
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Advantages of Database Approach
•
Redundancy can be reduced
•
Inconsistency can be avoided
•
The data can be shared
•
Standard can be enforced
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SOCSAMS e-learning
Advantages of Database Approach
•
Redundancy can be reduced
•
Inconsistency
can besystem,
avoided
In a file processing
each user group maintains
its own files, resulting in a considerable amount of
• Theredundancy
data can be
of shared
the stored data. In database approach
data can be stored at a single place or with controlled
• Standard
can be
enforced
redundancy
under
DBMS.
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SOCSAMS e-learning
Advantages of Database Approach
•
Redundancy can be reduced
•
Inconsistency can be avoided
•
The data can be shared
A database is said to be inconsistent, when there will be
occasions
the redundant entries will not
• Standard
canon
be which
enforced
agree. A database that is in an inconsistent state is
capable of supplying incorrect or conflict information.
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Advantages of Database Approach
A DBMS allows the sharing of database under its
control by any number of applications programs or
• Redundancy
reduced of new applications may
users. The can
data be
requirements
be satisfied without having to create any new stored
• Inconsistency
can be avoided
files.
•
The data can be shared
•
Standard can be enforced
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SOCSAMS e-learning
Advantages of Database Approach
•
Redundancy
cancontrol
be reduced
With central
of the database, the DBA can
ensure that all applicable standards are followed in the
• Inconsistency
be data.
avoided
representationcan
of the
Standards => company, installation, departmental,
• Theindustry,
data can
be shared
national
and international standards.
•
Standard can be enforced
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Advantages of Database Approach
Continue…
•
Data Independence
•
Security restrictions can be applied
•
Integrity can be maintained
•
Multiple user interfaces
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Advantages of Database Approach
Continue…
•
Data Independence
•
Security
be applied
Data restrictions
Dependence can
=> the
knowledge of the data
organization and access technique is built into the
• Integrity
can be
maintained
application
logic.
It is impossible to change the storage
structure or access strategy without affecting the
• Multiple
user interfaces
application.
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Advantages of Database Approach
Continue…
•
Data Independence
•
Security restrictions can be applied
•
Integrity can be maintained
• DBA can define authorization checks to be carried
out whenever
access to sensitive data is attempted
• Multiple
user interfaces
• Different checks can be established for each type of
access to each piece of information in the database.
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Advantages of Database Approach
•
Continue…
Data integrity refers to the correctness and completeness
of data
in a database=> by providing
Data• Checks
Independence
• Constraints
(to datarestrictions
items within a record
or relationships
Security
can be
applied between records)
•
Integrity can be maintained
•
Multiple user interfaces
•
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Advantages of Database Approach
Continue…
•
Data Independence
•
A DBMS provides a variety of interfaces
• Query language
Security
restrictions
can
be applied
• Programming
language
interfaces
• Forms and codes
• Menucan
driven
Integrity
beinterfaces
maintained
•
Multiple user interfaces
•
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SOCSAMS e-learning
Advantages of Database Approach
Continue…
•
Improved Backup and Recovery
•
Support for Concurrent Transactions
•
Conflicting requirements can be balanced
A backup and recovery subsystem is responsible for
recovering data from hardware and software failures.
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SOCSAMS e-learning
Advantages of Database Approach
Continue…
•
Improved Backup and Recovery
•
Support for Concurrent Transactions
•
Conflicting requirements can be balanced
A DBMS allows multiple transactions to occur
simultaneously.
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SOCSAMS e-learning
Advantages of Database Approach
Continue…
•
Improved Backup and Recovery
•
Support for Concurrent Transactions
•
Conflicting requirements can be balanced
By knowing the overall requirements of the enterprise –
the DBA can structure the database system to provide
an overall service that is “best for the enterprise”.
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Questions ?
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