lect 12 database system
TRANSCRIPT
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Fundamentals of
Database Systems
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What is a Database?
A database is any organized collection of data.Some examples of databases you mayencounter in your daily life are:
a telephone book T.V. Guide
airline reservation system
motor vehicle registration records
papers in your filing cabinet
files on your computer hard drive.
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What is a Database?
A collection of related facts
Filing CabinetFiling CabinetHard disk full of dataHard disk full of data
DiaryDiary
Library
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Basics of Database
A Database consists of four elements:
Data: Data is nothing but the facts
Relationship : It represents the correspondencebetween the various data elements
Constraints : Constraints are the predicates thatdefine correct database state
Schema : It describes the organization of data
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Relationship Types
One-to-one (1:1)
One-to-many (1:M)
Many-to-many (M:M)
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Table
A table is the primary unit of physical storage
for data in a database.1
Usually a database contains more than one
table.
1) Stephens, R.K. and Plew. R.R., 2001. Database Design. SAMS, Indianapolis , IN.
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Table
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Field (Column)
a field
Customers
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Record (Row)
a record
Customers
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Why a Database System
Redundancy Can be controlled
Inconsistency can be avoided
Data can be shared Standards can be enforced
Security restrictions can be applied
Integrity can be maintained
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What is a DBMS?
DBMS - DataBase Management System
Multiple Billion dollar market for DBMS products and
services !
A software system for defining, constructing and
manipulating databases for various applications
DBMS may be general purpose (business
applications) or special purpose (biologicaldatabases, geographic information, ...)
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What is a Database System?
ApplicationApplication Programs/Queries
Software to Process
Queries/Programs
Software to Access
Stored Data
DATABASE SYSTEMDATABASE SYSTEM
DBMS SOFTWARE
Users/Programmers
Stored Database
Definition
(Meta-Data)
Stored
Database
DBMSDBMS
++DatabaseDatabase
==
Database SystemDatabase System
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Database System Components
T
he Stored Database A collection of related facts The DBMS The software that defines, constructs and
manipulates a database
The Applications The programs (in specific languages) that
manipulate the database The Users
People who use the database system, throughthe DBMS interface or through applicationprograms
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Database Users
Database administrators: responsible for authorizingaccess to the database, for coordinating andmonitoring its use, acquiring software, and hardwareresources, controlling its use and monitoring
efficiency of operations. Database Designers: responsible to define the
content, the structure, the constraints, and functionsor transactions against the database. They must
communicate with the end-users and understandtheir needs.
End-users: they use the data for queries, reports andsome of them actually update the database content.
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Levels of Abstraction
Views describe howusers see the data.
Conceptual schemadefines logicalstructure
Physical schemadescribes the files andindexes used.
Physical Schema
Conceptual Schema
View 1 View 2 View3
DB
Users
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Functions of DBMS
Transaction Management
Concurrency Control
Recovery Management Security Management
Language Interface
Storage Management Data Catalog Management
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Type of Database
Operational Database : It stores detailed dataneeded to support the business process andoperations of the company
Distributed Database : Many organizationsreplicate and distribute copies or part ofdatabase to network server
External Database : Database which is not
owned by the company
Hypermedia Database : Advanced Databasewhich uses hyper linking
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What is Data Warehousing?
Data warehousing is subject-oriented, integrated,time-variant, and non-volatile collection of data insupport of managements decision-making process.
a data warehouse is data management and dataanalysis tool
Data webhouse is a distributed data warehouse thatis implement over the web with no central datarepository
goal: is to integrate enterprise wide corporate datainto a single reository from which users can easilyrun queries
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Components of Data Warehouse
Summarized Data
Operational System ofRecords
Integration/Transformation Program Current Detail
Meta Data
Archives
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Data Warehouse Organization
I/T P Current Detail ArchiveOSR
Meta DataL S/D
H
S/D
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The benefits of data warehousing
The potential benefits of data warehousing
are high returns on investment..
substantial competitive advantage.. increased productivity of corporate decision-
makers..