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37 terms

DCB Data Input and Output

Daniel and Ian
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Data Input
The process of entering date into a computer system GIGO
Data Capture Forms
A table used for writing down data that is collected
Visual verification
Person who enters the data and checks visually for errors
Double entry verification
Two sets of data are entered and then compared, more expensive and time consuming but more accurate
Verification
Checking that the data entered is correct
Key-to-disk
Entering data written on a questionnaire or form using a keyboard and saving it
Direct data entry
Data directly entered into the computer
Input screen/Online form
Entering information into a form on the screen
Optical mark reader
Written data that is turned into digital data without having to type the data
Card reader
Using cards to store information
Sensors
Records information and inputs it at times and in locations where it would be difficult for a person to do it
Radio frequency identification (RFID)
Microchips that store information and can be read wirelessly
Field length
Checking the number of characters that are allowed to be stored in a field
Type check
Makes sure that the data is of the type expected. ie. 89 accepted, AB89 is not
Format check
Makes sure that the data is in the expected format. ie. dd/mm/yyyy
Range check
Makes sure data falls within a sensible range. ie. 0<dd<32
Presence check
Makes sure that data that is required is entered
Check digit
An extra digit added to a number that is calculated in a prescribed way that is known to the computer system, the check digit is then checked
Data Output
Many factors influence output design. One very important constraint is that output is dependent on the availability of the data it is derived from. If this is not already stored within the lCT system when output is requested, then the required Output cannot be generated .
General Guidelines
Audience, Usage of Tables, Diagrams, Graphs, Layouts, Timing and Accessibility. Use simple language to avoid the audience from being confused.
Internal Audience
This type of output is produced for the audience within the organization.
External Audience
This type of output is produced for the audience outside the organization.
Turnaround Audience
This type of output is produced for the external audience but it is expected that they will add data to it and return it to the organization. An example of a turnaround document is Cl printed questionnaire or data capture form.
Use of Tables, Diagrams and Graphs
Tables. diagrams and graphs can be used to summarize information. They should
be clearly labeled. with legends provided for all abbreviations.
Tables
Tables are often produced in spreadsheets and exported to other applications.
Pie Diagram
A pie diagram gives us information about relative importance of the takings from the sales of the different types of meals.
Validation
You could set up a validation check to make sure that only 'F' or 'M' were entered. Similarly 'Male' and 'Female' could easily be validated if this was being entered in an interactive form on a website.
Encoding Data
Codes can be used to represent lengthy snippets of language. It can be found in our everyday devices from mobile phones to laptops and cars!
Examples of Encoding Data
'1' could mean 'Can you switch the television on?'
'2' could mean 'Which channel would you like to watch?'
'3' could mean 'I'd like to have pasta for dinner!'
Why is a range check for dates important?
As if there isn't a boundary then the numbers may be incorrect and invalid.
What are an advantage and a disadvantage for double entry verification?
One advantage is that the data will be almost 100% correct, one disadvantage is that this type of checking takes much longer.
What is key-to-disk data input?
When data is on physical media then recorded digitally manually.
Why are codes used?
They are used because:
-Data entry is easier.
-Data entry is faster.
-Less space is needed to store the data on backing storage.
-Setting up validation checks is easier.
-Privacy can be preserved.
-Output can be more concise.
Give an example of a data input device.
Keyboard, Mouse etc.
Codes
Selecting a code helps clarify what data needs to be entered.
Example of using codes
Codes are widely used in ICT systems. Another example would be a database for a school library where books are classified as 'fiction', 'non-fiction' or 'reference' and there are other resources like 'CDs', 'DVDs' and 'Magazines' that can be borrowed.
Coding these as 'F', 'N', 'R', 'C', 'D', 'M' would speed up data input, reducing the space needed on backing storage and make output more concise.
Encoding Continued
Computers encode the language we use. You type the letter 'A' on your keyboard but it may be represented as a binary code in ASCII so that the computer can store and process it. The binary code is decoded before it is displayed for you to read.

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