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