Data Capture, Input Methods, and Output Methods Applied Database II.
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Transcript of Data Capture, Input Methods, and Output Methods Applied Database II.
Data Capture, Input Methods, and Output Methods
Applied Database II
Review Data Processing: Input, Process,
Output Transaction Processing
Data Entry Data Validation Data Processing and Revalidation Storage Output Generation Query Support
Data Capture
There are Three Main Approaches to Data Capture
Direct Data Entry Automatic Data Capture Methods The Data on a Form
Data Capture Data capture means obtaining data for a
computer. Collecting documents to be typed in Making measurements and keying in Asking people to fill in questionnaires
Automated data capture means obtaining data directly by an input device without using a keyboard.
Using document readers (OMR, MICR, OCR) Bar code readers Scanning pictures Using sensors for Data Logging
Data Capture Forms Data capture forms are designed to
have computer input data written on them. A membership subscription form A questionnaire A turnaround document
This is so that: Data is standardised with all records set
out in the same way; People collecting the data know what data
is required.
Turnaround Documents A turnaround document is produced by
a computer, has more data added to it, and it is then input to the computer again. Example: Gas Board meter reading
Advantages: Data which is already known to the computer
does not need to be written or keyed in again. The computer can recognise each individual
document using information it has already printed on it.
Design of Data Capture Forms Data capture forms should be designed
to be: Simple
Ask for the minimum of information Keep printed text to a minimum
Clear Give clear instructions Keep fields close to spaces for information/answers
Interesting If it looks attractive it is less effort to fill in
Data Capture Forms
Design techniques Fonts and Font Size Layout of the Form Prompts and Examples Entry Boxes Colour and Shading
Tick Boxes and Lists Example : The school registers
Questionnaires A survey is an operation to obtain
information by observation or by asking questions.
A questionnaire is a set of questions used in a survey to collect information from people.
The data collected must be easily analysed
Data Analysis Data from questionnaires must be
easily analysed and can be of several different types of closed questions: Questions requiring yes/no answers. Questions with several possible
answers giving a simple choice. Questions where the answer is a
number which measures a quantity.
Input Methods An input device is a peripheral which
accepts data and sends it to the CPU: Keyboard Mouse Document reader (OMR, OCR, MICR) Light pens and touch screens Sensors Scanner Joysticks and game controllers Microphone
Document Readers Optical Mark Readers
(OMR) OMR is a system of
reading lines or marks which have been made inexactly the right positions on a document (School registers).
uses light to detect the position of black marks on white paper.
Document Readers Optical Character Recognition
(OCR) Scanners read text and software
recognises the letters from their shapes.
Advantage: OCR is faster than typing! Disadvantage:
You need to buy a scanner and OCR software.
It is not completely accurate, and text would need proof-reading afterwards.
Document Readers Magnetic Ink Character Recognition
(MICR) An MICR reader recognises characters
formed from magnetic ink, used for bank cheques.
Advantages : Documents are difficult to forge. Documents can still be read after being written
on, folded, spilt on etc... Disadvantages :
M.I.C.R. readers and encoders are expensive. The system can only accept a few characters.
Bar Codes A bar code is a set of parallel printed lines
of differing thicknesses which are used to store coded information about an item.
Bar codes are read using a Bar Code Reader
Advantages a fast method of data entry eliminates possible human error
Disadvantages scratched or crumpled barcodes may cause
problems
Magnetic Stripes a short length of magnetic tape sealed
onto the surface or embedded in a card. usually contains information to identify the
ticket or card or its user Examples: credit cards; phone cards; smart card
Sensors
Many measuring devices (sensors) can be linked to computers. This requires special software and usually a special interface.
Many sensors are digital - they produce one of a distinct set of values.
Other sensors are analogue - they can produce any value within a given range of numbers.
Analogue signals would need to be converted to digital signals by an analogue-to-digital converter (ADC), before the computer can process the readings.
Sensors Examples : Sensors can measure -
temperature eg to control a heating system light eg to control automatic street lighting sound eg to measure noise pollution infra red eg photo cells may be used to detect a break
in a beam in a burglar alarm system. proximity eg to make sure robots do not crash into
walls pressure eg to make sure robotic 'hands' do not grip
an object too tightly. humidity eg to control an environment in a tropical
greenhouse. Data logging - a method of automatic data
capture where a reading from a sensor is input at regular intervals. This data can then be processed to provide analysis of the environment.
Sound / Speech Microphones and voice sensors are used to
input sounds. The computer will then analyses the sound and process the data.
MIDI (musical instrument digital interface) is used for the input of signals from an electronic instrument such as a keyboard to a computer for processing.
Analogue signals will need to be converted to digital using an analogue-to-digital converter. The process of converting analogue sound to digital data is called sampling
Input Control Include combination of manual and
computerized control To ensure accurately and preserving
data integrity Technique
Batch control ; source documents Online control
EXAM QUESTIONS1. A market researcher needs to find out what
snacks people prefer, how much they are prepared to pay and when they are most likely to buy snacks. He should also attempt to find out if there are any variation in tastes depending on age and sex.
a) Design a suitable questionnaire to collect the data.b) Describe two methods, other than a questionnaire,
that can be used to collect data.
EXAM QUESTIONS
2. A point-of-sale system in a supermarket includes a scanner attached to each till to read bar codes.The bar code on a tin of peas contains the item code and and a check digit.
a) Why does it not contain the price?b) What is the purpose of the check digit?c) The till receipt contains the name of the item and
the price. How is this information obtained?
Output Method
Output Method Pertaining to a device, process, or
channel involved with the transfer of data or information out of an information processing system
Two basic categories Output for immediate use by people Stored in computer-usable form
Output Generation Hardcopy; documents and reports Softcopy; forms: screens or panels
Output Device Monitor Laser Printers Inkjet Printers Graph plotter Sound Output Control Systems COM CAM
Output Control Balancing output total with input and
processing totals Auditing output report Providing distribution lists for all report Requiring signatures on predetermined form Providing delivery schedule for reports Requiring users to enter password Providing guidelines Securing sensitive data and information in an
inaccessible location