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TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector �C 9, Dwarka Institutional Area, New Delhi-75
Affiliated to Institution of G.G.S.IP.U, Delhi
BCA
DBMS
BCA 108
DBMS Basics
Keywords: Data, Database,DBMS

Database Management System
(DBMS)
? Database Management System (DBMS): A
software system used to create and maintain
database.
? Database System: The DBMS software having
data . Sometimes, the applications are also
included.

DBMS Functionality
? Define a database : in terms of data types,
structures and constraints
? Construct or Load the Database on a
secondary storage medium
? Manipulating the database : querying,
generating reports, insertions, deletions and
modifications to its content
? Concurrent Processing and Sharing by a set of
users and programs �C yet, keeping all data
valid and consistent

Main Characteristics of the Database
Approach
? Self-describing nature of a database system: A
DBMS catalog stores the description of the
database. The description is called meta-data).
This allows the DBMS software to work with
different databases.
? Insulation between programs and data: Called
program-data independence. Allows changing
data storage structures and operations without
having to change the DBMS access programs.

Main Characteristics of the Database
Approach
? Data Abstraction: A data model is used to
hide storage details and present the users
with a conceptual view of the database.
? Support of multiple views of the data: Each
user may see a different view of the
database, which describes only the data of
interest to that user.
? Sharing of data and multiuser transaction
processing :

Instances and Schemas
? Schema �C overall description of the database
? ex: cust_id : string;
cust_name : string;
cust_street : string;
cust_city : string;
? 2 Types of schema :
�C Physical schema: database design at the physical level
�C Logical schema: database design at the logical level
? Instance �C the actual content of the database at a
particular point in time

Data independence
? Physical Data Independence �C the ability to
modify the physical schema without changing
the logical schema
? Logical Data Independence- the ability to
modify the logical schema without changing
the external view

The Entity-Relationship Model
? It is collection of entities and relationships
�C Entity: real life ��object�� in the enterprise
�C Relationship: an association among several
entities

Database Users
Actors on the scene
�C Database administrators(DBA): responsible for
authorizing access to the database, for co-ordinating
and monitoring its use.
? Casual : access database occasionally when needed
? Na?ve or Parametric : they know little about Dbms and
databases.
? Sophisticated : these include business analysts,
scientists, engineers, others thoroughly familiar with
the system capabilities..

Advantages of Using the Database
Approach
? Controlling redundancy in data storage and in
development and maintenence efforts.
? Sharing of data among multiple users.
? Restricting unauthorized access to data.
? Providing persistent storage for program
Objects (in Object-oriented DBMS��s �C
? Providing Storage Structures for efficient
Query Processing

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Database Management System

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