Transcript CGSCH 05 Wiley 2nd ghzk

CHAPTER 5
MANAGING ORGANIZATIONAL
DATA AND INFORMATION
Basics of Data Arrangement
and Access
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Field - a logical grouping of characters into a word, a small
group of words, or a complete number
Record - a logical grouping of related fields
File - a logical grouping of related records
Database - a logical grouping of related files
Entity - a person, place, thing, or event about which
information is maintained
Attribute - each characteristic or quality describing a
particular entity
Primary Key - field that uniquely identifies the record
Secondary Key - field that has some identifying
information, but typically does not identify the file with
complete accuracy
Problems with Traditional File Approach
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data redundancy
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data inconsistency
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data isolation
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security
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data integrity
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application/data independence
Database : The Modern Approach
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Creating a Database
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Conceptual design - an abstract model of the
database from the user or business perspective
Physical design - shows the way a database is
actually arranged with a storage devices
Entity-relationship (ER) modeling
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process of planning the database design
Entity classes  Instance  Identifiers  Relationships
Normalization
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method for analyzing and reducing a relational database to its
most streamlined form for minimum redundancy, maximum
data integrity, and best processing performance
Database Management Systems
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A software program (or group of programs) that
provides access to a databases
Permits an organization to store data in one location,
from which it can be updated and retrieved
Provides access to the stored data by various
application programs
Provides mechanisms for maintaining the integrity of
stored information, managing security and user
access, recovering information when the system fails,
and accessing various database functions form within
an application written in a third-generation, fourthgeneration, or object-oriented language
DBMS Components
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4 Main Components
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Data model
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defines the way data are conceptually structured
Data definition language (DDL)
defines what types of information are in the
database and how they will be structured
 functions of the DDL
 provide a means for associating related data
 indicate the unique identifiers (or keys) of the
records
 set up security access and change restrictions
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DBMS Components (continued …)
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Data manipulation language (DML)
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Structured query language (SQL) - most popular
relational database language
Data Dictionary
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stores definitions of data elements and data
characteristics
THE END
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