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Transcript of data & database
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8/7/2019 data & database
1/23
Technology Guide 3
Data and Database
T3-1
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8/7/2019 data & database
2/23
IT for Management
Prof. Efraim Turban
T3-2
File Management
Hierarchy of data for a computer-based file
Record
Field Field
Byte Byte
Bit Bit
Record
FieldField
ByteByte
BitBit
File
Database
File
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-3
File Management Entity
a person, place, thing, or event on which
we maintain information Attribute
characteristic or quality describing aparticular entity
corresponds to a field
Key Field a file that uniquely identifies that record
an identified filed
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-4
Accessing Records from
Computer Files
Sequential File Organization
data records must be retrieved in thesame physical sequence in which theyare stored
magnetic tape
Direct or Random File Organization Users can access records in an
sequence, without regard to actualphysical order on the storage medium
magnetic disks
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-6
Database and
Database Management Systems Database
an organized logical grouping of related files
no data redundancy, data isolation, and data
inconsistency
Database Management Systems (DBMS)
a program that provides access to a database
permits an organization to centralize data,
manage them efficiently, and provide access
to the stored data by application programs
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-7
Specialized Database Geographical Information Database
contains locational data for overlaying on
maps or images
Knowledge Database
stores decision rules used to evaluate
situations and helps users make decisionslike an expert
Multimedia Database
Stores data on many media sounds,
video, images, graphic animation, and text
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-8
Data Definition Language
(DDL)
Schema
the logical description of the entiredatabase and the listing of all thedata items and the relationshipsamong them
Subschema the specific set of data from the
database that is required by eachapplication
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IT for Management
Prof. Efraim Turban
T3-9
Data Manipulation language
(DML)
Structured Query Language (SQL)
combines both DML and DDL features offers the ability to perform complicated
searches with relatively simple statements
Query-by-example (QBE) allows users to select a table and chooses
the fields to be included in the answer as
the example he provided
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-10
Data Dictionary
Data dictionary is a file that storesdefinitions of data elements and
data characteristics such as usage,
physical representation, ownership,authorization, and security
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-11
Hierarchical Database Model
It relates data by rigidly structuring data
into an inverted tree A single root or master field (Key)
identifies the type location, or ordering of
the records A variable number of subordinate fields
defines the rest of the data within a record
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-12
Network Database Model
It creates relationships among data
through a linked-list structure inwhich subordinated records can be
linked to more than one parent
Pointers
link subordinates and parents
storage addresses that contain the
location of the related record
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-13
Relational Database Model It is based on the simple concept of
tables in order to capitalize on
characteristics of rows and columns
of data, which is consistent with
real-world business situations
Relations : table Record : row of data
Field : column of data
Object-relational Database Systems
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-14
Creating Database
Conceptual Design
an abstract model of the databasefrom the user or business perspective
Describes how the data elements in
the database are to be grouped
Physical Design
shows how the database is actually
arranges on direct access storage
devices
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-15
Entity-relationship Modeling Entity is something that can be identified
in the users work environment
Instance of an entity is the representation
of a particular entity
Attributes describe the entitys
characteristics
Identifiers are attributes that identify
entity instances
Relationships can include many entities
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-16
Entity-Relationship Diagram
Table
ClassStudent Professor
Name
ID Number
Major
Departmet
Class Taught
Name
Attribute
Entity Relationship
1:N
One to many
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-17
Normalization of
Relational Databases
Functional Dependency
a relationship between or
among attributes, where,
given the value of one
attribute, we can obtain the
value of another attribute
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-18
Emerging Database Models
Multimedia Database : an additionaldatabase that enables end users to quickly
retrieve and present completes data that
involve many dimensions
Deductive Databases
Object-oriented Database : used for OOprogramming
Multimedia and Hypermedia Database
: analogous to textual and numeric data
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-19
Data Warehouses
It is an additional database that is designed to
support DSS, EIS, online analytical process(OLAP), and other end-user activities.
It can provide an executive view of data
and a unified corporate picture to the end-
users by combining the data from manyoperational systems and incompatible
databases without affecting the performance
of the running operational systems
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-20
Database Topology Centralized Database has all the related
files in one physical location
Distributed Database has completecopies of a database, or portions of a
database, in more than one locations
Replicated Database has complete copiesof the entire database in several locations
Partitioned Database is subdivided, sothat each location has a portion of the entire
database
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8/7/2019 data & database
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IT for Management
Prof. Efraim Turban
T3-21
Physical vs. Logical Data View
Physical View
deals with the actual, physicalarrangement and location of data in the
direct access storage devices (DASD)
Logical View
represents data in a format that is
meaningful to a user and to the software
programs that process that data
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IT for Management
Prof. Efraim Turban
T3-22
Database Management
Database Design
Database Implementation
Database Administrators
responsible for ensuring that the
database fulfills that users business
needs, in terms of functionality s
well for the data itself
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Copyright 2001 John Wiley & Sons, Incorporated. All
rights reserved. Reproduction or translation of this workbeyond that permitted in Section 117 of the 1976 United
States Copyright Act without the express written
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for further information should be addressed to the
Permissions Department, John Wiley & Son, Inc.Adopters of the textbook are granted permission to make
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responsibility for errors, omissions, or damages, caused
by the use of these programs or from the use of the
information contained herein.
IT for Management
Prof. Efraim Turban
6-23