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Information Systems

Data Management

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Bit:Bit represents the smallest unit of dataa computer can handle. 0or 1.

Byte:A group of 8 bits; represents a single character, like a letter, numberetc.

Field:Agroup of Characters into a word, a group of words or a complete

number, such as a persons name or age.

Record:A group of related fields. Like: Single students Name, Course

Taken, Grade etctogether.

File:A group of records of a same type. Like: All Students Academic sts.

File Processing (Foundation Data Concepts)

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Sequential File Organization:

Random File Organization:

Index Access Method:

File Organization

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File Management ConceptA. kept updates by

a. Adding recordsb. Deleting recordsc. Changing data in records

B. Data Validation:process of checking data as it is entered

into a file to ensure accuracy. Incase of traditional file

system computer programs perform validation.

C. Data Availabilityis accomplished through regular backupsand offsite storage

D. Securityprevents unauthorized access

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Advantages & Disadvantages of File Processing

Advantages

Simple to use

Some information systems only

need a single file

Sequential files are used in simple

cases

Disadvantages

Data redundancyData may be duplicated

Lack of data-sharing and availability

Difficult to access data from more than one

file at a time

Program-Data dependencePrograms

must have specific instructions for each file,

creating dependencies

Lack of flexibilityCannot delver Ad hoc

reportsPoor securityData available in multiple

files resulting in poor security

Requires extra storageBecause data

duplication

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DBMS

The Contemporary Database Environment

Database Processing

Databases can overcome some file processing disadvantages

All data is stored together

A DBMS allows creation, update, and deletionof data

Users & programmers access data through the DBMS(DBMS acts as an interface)

Traditional File Processing Database Processing

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d i d f b i

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DBMS

Data Redundancy:Data stored here only

once. So data is treated as one collection;

one files.

Data Processing:Since one collection,

dbase software process data with least

difficulty.

Dependency:Programs arent dependent

on the data in the database. The database

can be changedwithout changing every

program that uses the database.

Advantages & Disadvantages of Database Processing

Advantages

Expensive:One source of expenseis the

cost of the database software.

Damage:dbase software that processing all

data must be stored on the same disk.

Damage to that disk means all data is lost.

Development complexity:Development

of IS usually requires more careful planning

and is more time-consuming than in file

processing systems.

Disadvantages