B061 4.0 Manipulating data Flashcards
Different types of data
Text/Alphanumeric
Numeric (Integer,Real numbers,Currency,percentages, Fractions)
Date and time
Boolean or Logical (yes/no open/closed Male/female On/off )
Give examples of data collection
Questionnaires Application forms Online forms Optical Mark Recognition Bar code readers Biometrics RFID tags
What are the Advantages to OMR
It is a fast method of inputting large amounts of data at a very high rate
Only one computer needed ton correlate batch of data therefore lower cost
OMR is a more accurate method of data entry than manually keying data
Disadvantages of OMR
The marks may not read correctly if spaces aren’t completely filled in
Not Suitable for text input ; mainly used for multi-choice input
Needs specially prepared stationary as well as a OMR reader also data needs to inputted into specific perimeters
Advantages of barcode readers in electric point of sale situations
Automatic input therefore quick to enter
Bar code errors easily avoided via warning systems
Check digit software included
Easy to change data in databases and this allows for updates
Can be linked to stock control therefore allowing for a creation of an automatic re-ordering
Disadvantages of barcode readers in electric point of sale situations
Other alternative methods needed in case system fails
If barcodes are missing data will need to be added manually
New products have to be added to the database otherwise the system would be out of date
Training required to use the hardware
Advantages of Chip and Pin/ Magnetic Strip Recognition
Simple to use and cheep to produce
Data can be altered if necessary
Security has been improved by the use of PIN numbers which must be entered into a machine to confirm that you are the rightful card owner
disadvantages of Chip and Pin/ Magnetic Strip Recognition
It has very limited storage capacity for data
Data can easily be destroyed by strong magnetic fields
It is not always secure as thieves can obtain the readers and read the data on the card
Advantages of voice recognition
Quicker method of entering data than using using a keyboard
Ideal methods for disabled users who can’t easily use keyboards
Helps to prevent repetitive strain injury
Disadvantages of voice recognition
Software needs to be trained to recognise an individual voice and accent accurate data entry
The user has to learn a range of commands and sometimes there are problems distinguishing between input text and commands
Excessive background noise can cause errors as the speech input is quality is reduced
What is Biometrics recognition and how does it work
It is used to identify an individual by either Physiological such as finger prints iris recognition
Behavioral such as voice recognition
What are RFID tags and how do they work
Radio frequency identification tags are fixed to products like barcode. They use the antenna to communicate with RFID reader or scanner for tracking purposes
What is an Absolute cell reference
When a formula is copied from one cell to another may be a need to maintain an absolute cell reference with the original cells. This is can be achieved by referencing a cell as $A$1 which when copied will remain $A$1
What are flat file Databases
A flat file database is a simple database that is composed of one table often used in the creation of spreadsheets each row is know as a record
What are relational Databases
The data is stored in separate tables or entities
All the data tables are linked by key fields
Microsoft Access is an example of Relational Databases management systems
List the verification types
Presence check Data Type check Length check Check Digits Range checks Format Check
Define Presence check
Checks that data has been entered into a field and that is has not been left blank
Define Data Type check
Checks that a value entered is of a particular data type.
Define Length check
Checks than an entered value such as mobile phones is no longer than a particular number of characters
Define Check Digits
These are normally digits on a ISBN book code that are used as a part of a calculation to ensure that the code entered is valid code.
Define Range checks
Checks that an entered value falls within a particular range
Define Format Check
Check that an entered value has a particular format.
what are the two mains ways to verify data
Visual checks
Double entry
What is a Batch total in the context of Validation
This is a check for missing records where the all numerical records for a batch are summed together.
What is a Hash total in the context of Validation
this a check used for detecting errors in data transmission. A hash total is calculated from several fields in a file or table before and after data transmission and a comparison is made between the original and final data to detect a difference or an error
