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Data Types

A presentation summarizing Chapter 5 of the IGCSE Information and Communication Technology Text Book (2010).

Richard Umboh

on 26 November 2013

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Transcript of Data Types

Data Structure
Data Types
Chapter 5
Consistency of data is maintained
Replication of data is minimized
Expansion of databases due to new applications is relatively easy
Data is much more safe and secure, due to it being easy to monitor and maintain.
This can be done through the use of front ends. The database would only be visible to the administrator.
Relational Databases
Consist of separated but related tables.
Each table's primary key field is a also a field in at least another table
Data from separate tables may be combined to form a report
Data does not need to be repeated, unlike flat file structures
Data among tables are only connected through the primary key field
Quick retrieval of data
Easy database expansion
Data only needs to be edited in one table, due to the relational structures
Foreign keys may also be used to relate tables to one another. A table's foreign key is a primary key in another table.
Analogue and Digital Data
Data worked by computers
Data is processed in numbers (digits), hence the name 'digital'
Data that has been stored systematically to allow easy access, searching, and manipulation

Reasons for the use of databases:
Digital data:
Conversion of data between analogue and digital is required because computers are only able to understand analogue data
Conversion of Data
Analogue to digital converter (ADC):
To use an analogue input device, you would need to use an ADC as computers cannot understand analogue data
Example: Microphones connected to computers require an ADC so that the analogue signals of your voice may be converted into digital data the computer understands
Digital to analogue converter (DAC):
To use an analogue output device, you would need a DAC so that the digital signals sent from the computer may be converted into analogue signals
Example: Speakers connected to computers require a DAC so that the digital data sent from the computer can be converted by the DAC into analogue signals which in turn are converted into sound which you can hear
IGCSE Information and Communications Technology Textbook (2010)
There are many types of data that can be found, both in the real and digital worlds. Real world data must usually be measured physically. To be able to store and work with this data on a computer, it must be converted into digital form. Databases may be used to systematically store this data in a way that allows easy access and searching at a later point.
Relational Databases
Analogue and Digital Data
Conversion of Data
Types of Data
Common data types found in standard computer systems:
Logical/Boolean: Only two values, true or false (Yes/No, 1/0, etc.)
AND operator: Condition is true in both criteria
OR operator: Condition is true in either criteria
Alphanumeric/Text: The alphabet, numbers, and other symbols (@, $, & ,etc. )
Text: Includes only the alphabet
Alphanumeric: Includes the alphabet, numbers, and the other symbols
Numeric: Involves the digits 0-9. May be positive or negative
Integer: Only whole numbers (e.g. 1997)
Real: Contains decimals (e.g. 19.97)
Date: Data found in a calendar (days, months, years, etc.)
Has many acceptable forms:
dd/mm/yyyy (e.g. 07/09/1997)
dd/mm/yy (e.g. 07/09/97)
dd mmmm yyyy (e.g. 7 September 1997)
Discussion Cube
Data Structures
Commonly, data structures are composed of three levels/components:
Types of Data
File: This is where the data is stored. Files also contain records.
Record: The data related to one object. Usually arranged in rows. Records then contain fields.
Field: One item or piece of data. Usually arranged in columns. Each field in a record contains different data and data types.
Primary Key Field: The field used to uniquely identify each record. Usually in numeric integer data type.
Flat file structures are large files that contain all the records of a database in one table
Analogue data:
Real world, physical measurements (e.g. length, speed, etc.)
They vary continuously and smoothly, and within a certain range may provide infinite values
They are measured with analogue devices which present the data on a physical/analogue scale
A lot of analogue data is gathered and measured by sensors
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