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 DATABASE
 DATABASE
ENVIRONMENT
 WHY STUDY DATABASE
 DBMS & ITS FUNCTIONS
 STRUCTURE OF DBMS
 DBA
Database:
A very large, integrated collection of data.
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A Database is a well organized collection of data that are
related in a meaningful way which can be accessed in
different logical orders but are stored only once
The record of students maintained by your college is a
useful database
Models a real-world enterprise
◦ Entities (e.g., teams, games)
A Database Management System (DBMS) is a software
system designed to store, manage, and facilitate access to
databases.
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DATA BASE SYSTEM ENVIRONMENT
Database
System
Stored data
base
definitoin
(META DATA)
DBMS
S/W
Stored
Database
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The database system contains not only the database itself
but also a complete definition or description of the database
structure and constraint. This definition is stored in the system
catalog.
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The information stored in the catalog is called metadata that
is the “data about the data”
An important property of database system is that the structure
of data files is stored in the DBMS catalog separately from the
access program.
We call this property as program-data-independence .
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Due to this property we can change the structure of
data files in the catalog but no need to change the
programs.
The Purpose of the database system is to provide an
environment that is both convenient an efficient to use in
Retrieving information from the database
 Storing information into the database
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Shift from computation to information
◦ always true for corporate computing
◦ Web made this point for personal computing
◦ more and more true for scientific computing
Need for DBMS has exploded in the last years
◦ Corporate: “customer relationship mgmt”, “supply chain mgmt”,
“data warehouses”, etc.
◦ Scientific: digital libraries, Human Genome project, NASA Mission
to Planet Earth, physical sensors, grid physics network
DBMS encompasses much of CS in a practical discipline
◦ OS, languages, theory, AI, multimedia, logic
◦ Yet traditional focus on real-world apps
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DBMS is the software that interprets and processes user’s request to
retrieve information from a database
DBMS provides security facilities in a variety of forms, both to prevent
unauthorized access and to prevent authorized users from accessing
data concurrently without any inconsistency in the database
The primary purpose of a DBMS which is basically a collection of
programs is to allow a user to store, update, retrieve data.
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Data Definition
DBMS must be able to access data
definition in source form and convert them to the
appropriate object form. In other words DBMS must
include language processor component for each of the
various data definition language(DDL).
Data Manipulation
DBMS must include a DML processor
component. The DBMS must be able to handle request
from the user to see, retrieve, update , delete or add the
new record to the database.
t
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DATA SECURITY AND INTEGRITY
DBMS must monitor user request &
reject any attempt to violate the security & integrity rules define by the
DBA.
DATA DICTIONARY
The dictionary contains data about the data rather
than the raw data.
Data Dictionary contains the information about entities, attributes,
mapping etc.
DBMS should perform all the functions as efficiently as possible.
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A typical DBMS has a layered
architecture.
The figure does not show the
concurrency control and recovery
components.
Each database system has its own
variations.
These layers
must consider
concurrency
control and
recovery
Query Optimization
and Execution
Relational Operators
Files and Access Methods
Buffer Management
Disk Space Management
DB
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DBMS vendors, programmers
◦ Oracle, IBM, MS, Sybase, …
End users in many fields
◦ Business, education, science, …
DB application programmers
◦ Build enterprise applications on top of DBMSs
◦ Build web services that run off DBMSs
Database administrators (DBAs)
◦ Design logical/physical schemas
◦ Handle security and authorization
◦ Data availability, crash recovery
◦ Database tuning as needs evolve
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DBA is the person or the group of persons who is responsible for the
management of the database.
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The DBA is responsible for defining the database structure, storage
structure and the access methods, authorizing access to the database by
grant the permission to the user
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