Database management system (dbms)

Submitted By:
Odisha Electronics Control Library
Database Management System
1
9/3/2021
Presented by:
Md. Sumon Fakir
ID# 173002024
Dept of CSE
Supervised by:
Mr. Utsha Das
Lecturer of CSE
(GUB)

Contents
 Introduction
 Purpose of DBMS
 Architecture of DBMS
 levels of DBMS
 Advantage of DBMS
 Disadvantage of DBMS
 Conclusion
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9/3/2021

Introduction
A Database Management System (DBMS), or simply a Database
System (DBS) consist of :
 A collection of interrelated and persistent data (usuallyreferred
to as the database (DB)).
 A set of application programs used to access, update and
manage that data (which form the data management system
(MS)).
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Purpose of DBMS
1. Data redundancy and inconsistency
 Same information may be duplicated in several places.
 All copies may not be updated properly.
2. Difficulty in new program to carry out each new task
2. Data isolation —
 Data in different formats.
 Difficult to write new application programs.
 files and formats
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Purpose of DBMS …
Security problems
Every user of the system should be able to access only the data
they are permitted to see.
 E.g. payroll people only handle employee records, and cannot
see customer accounts; tellers only access account data and
cannot see payroll data.
Integrity problems
 Data may be required to satisfy constraints.
 E.g. no account balance below $25.00.
 Again, difficult to enforce or to change constraints with the
file-processing approach.
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Architecture of DBMS
 There are following three levels or layers of DBMS
architecture:
 1. External Level
 2. Conceptual Level
 3. Internal Level
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levels of DBMS architecture
 External Level: - External Level is described by a schema i.e.
it consists of definition of logical records and relationship in
the external view.
 Conceptual Level: - Conceptual Level represents the entire
database. Conceptual schema describes the records and
relationship included in the Conceptual view. .
 Internal Level: - Internal level indicates hoe the data will be
stored and described the data structures and access method to
be used by the database.
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Advantage of DBMS
 Controlling Redundancy
 Sharing of Data
 Data Consistency
 Integration of Data
 Integration Constraints
 Data Security
 Data Independence
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Disadvantage of DBMS
 Cost of Hardware and Software
 Cost of Data Conversion
 Cost of Staff Training
 Appointing Technical Staff
 Database Damage
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Conclusion
 Data independence and efficient access.
 Reduced application development time.
 Data integrity and security.
 Uniform data administration.
 Concurrent access, recovery from crashes.
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9/3/2021

Database management system (dbms)

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